Conditions for Santa Rosa, CA
(Sonoma County)
Drought Indicators
Indicators are variables used to describe drought conditions (e.g., precipitation, temperature, streamflow, groundwater and reservoir levels, soil moisture, and snowpack). In order to get a complete picture of drought conditions, several drought indicators should be examined.
| Exceptional Wet | Extreme Wet | Severe Wet | Moderate Wet | Abnormal Wet | Neutral | Abnormal Dry | Moderate Drought | Severe Drought | Extreme Drought | Exceptional Drought |
| 0 percentile | 2 | 5 | 10 | 20 | 30 | 70 | 80 | 90 | 95 | 98 100 |
Exceptional Wet Exceptional Drought
Precipitation Conditions
Inches of Precipitation
This location received less than 0.01 inch of precipitation during this 7-day period.
This location received 0.01–0.5 inch of precipitation during this 7-day period.
This location received 0.5–1 inch of precipitation during this 7-day period.
This location received 1–2 inches of precipitation during this 7-day period.
This location received 2–4 inches of precipitation during this 7-day period.
This location received 4–6 inches of precipitation during this 7-day period.
This location received 6–8 inches of precipitation during this 7-day period.
This location received more than 8 inches of precipitation during this 7-day period.
Percent of Normal Precipitation (%)
<25% of Normal
Precipitation was only 0% to 25% of the historical average for this location, compared to the same date range from 1991–2020.
25%–50% of Normal
Precipitation was 25% to 50% of the historical average for this location, compared to the same date range from 1991–2020.
50%–75% of Normal
Precipitation was 50% to 75% of the historical average for this location, compared to the same date range from 1991–2020.
75%–100% of Normal
Precipitation was 75% to 100% of the historical average for this location, compared to the same date range from 1991–2020.
100%–150% of Normal
Precipitation was 100% to 150% of the historical average for this location, compared to the same date range from 1991–2020.
150%–200% of Normal
Precipitation was 150% to 200% of the historical average for this location, compared to the same date range from 1991–2020.
200%–300% of Normal
Precipitation was 200% to 300% of the historical average for this location, compared to the same date range from 1991–2020.
>300% of Normal
Precipitation was greater than 300% of the historical average for this location, compared to the same date range from 1991–2020.
Percent of Normal Precipitation (%)
<25% of Normal
Precipitation was only 0% to 25% of the historical average for this location, compared to the same date range from 1991–2020.
25%–50% of Normal
Precipitation was 25% to 50% of the historical average for this location, compared to the same date range from 1991–2020.
50%–75% of Normal
Precipitation was 50% to 75% of the historical average for this location, compared to the same date range from 1991–2020.
75%–100% of Normal
Precipitation was 75% to 100% of the historical average for this location, compared to the same date range from 1991–2020.
100%–150% of Normal
Precipitation was 100% to 150% of the historical average for this location, compared to the same date range from 1991–2020.
150%–200% of Normal
Precipitation was 150% to 200% of the historical average for this location, compared to the same date range from 1991–2020.
200%–300% of Normal
Precipitation was 200% to 300% of the historical average for this location, compared to the same date range from 1991–2020.
>300% of Normal
Precipitation was greater than 300% of the historical average for this location, compared to the same date range from 1991–2020.
This map shows total precipitation (in inches) for the past 7 days. Dark blue shades indicate the highest precipitation amounts.
This map shows precipitation for the past 30 days as a percentage of the historical average (1991–2020) for the same time period. Green/blue shades indicate above-normal precipitation, while brown shades indicate below-normal precipitation.
This map shows precipitation for the past 60 days as a percentage of the historical average (1991–2020) for the same time period. Green/blue shades indicate above-normal precipitation, while brown shades indicate below-normal precipitation.
Precipitation data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.
Precipitation data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.
Precipitation data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.
Drought is defined as the lack of precipitation over an extended period of time, usually for a season or more, that results in a water shortage. Changes in precipitation can substantially disrupt crops and livestock, influence the frequency and intensity of severe weather events, and affect the quality and quantity of water available for municipal and industrial use.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreDrought is defined as the lack of precipitation over an extended period of time, usually for a season or more, that results in a water shortage. Changes in precipitation can substantially disrupt crops and livestock, influence the frequency and intensity of severe weather events, and affect the quality and quantity of water available for municipal and industrial use.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreDrought is defined as the lack of precipitation over an extended period of time, usually for a season or more, that results in a water shortage. Changes in precipitation can substantially disrupt crops and livestock, influence the frequency and intensity of severe weather events, and affect the quality and quantity of water available for municipal and industrial use.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreTemperature Conditions
Maximum Temperature (°F)
<0°F
The 7-day average daily maximum temperature is below 0°F.
0–10°F
The 7-day average daily maximum temperature is between 0–10°F.
10–20°F
The 7-day average daily maximum temperature is between 10–20°F.
20–30°F
The 7-day average daily maximum temperature is between 20–30°F.
30–40°F
The 7-day average daily maximum temperature is between 30–40°F.
40–60°F
The 7-day average daily maximum temperature is between 40–60°F.
60–70°F
The 7-day average daily maximum temperature is between 60–70°F.
70–80°F
The 7-day average daily maximum temperature is between 70–80°F.
80–90°F
The 7-day average daily maximum temperature is between 80–90°F.
90–100°F
The 7-day average daily maximum temperature is between 90–100°F.
>100°F
The 7-day average daily maximum temperature is between greater than 100°F.
Departure from Normal Max Temperature (°F)
>8°F Below Normal
The average maximum temperature was more than 8°F colder than normal for this location.
6–8°F Below Normal
The average maximum temperature was 6–8°F colder than normal for this location.
4–6°F Below Normal
The average maximum temperature was 4–6°F colder than normal for this location.
3–4°F Below Normal
The average maximum temperature was 3–4°F colder than normal for this location.
1–3°F Below Normal
The average maximum temperature was 1–3°F colder than normal for this location.
0–1°F Below Normal
The average maximum temperature was 0–1°F colder than normal for this location.
0–1°F Above Normal
The average maximum temperature was 0–1°F warmer than normal for this location.
1–3°F Above Normal
The average maximum temperature was 1–3°F warmer than normal for this location.
3–4°F Above Normal
The average maximum temperature was 3–4°F warmer than normal for this location.
4–6°F Above Normal
The average maximum temperature was 4–6°F warmer than normal for this location.
6–8°F Above Normal
The average maximum temperature was 6–8°F warmer than normal for this location.
>8°F Above Normal
The average maximum temperature was more than 8°F warmer than normal for this location.
Departure from Normal Max Temperature (°F)
>8°F Below Normal
The average maximum temperature was more than 8°F colder than normal for this location.
6–8°F Below Normal
The average maximum temperature was 6–8°F colder than normal for this location.
4–6°F Below Normal
The average maximum temperature was 4–6°F colder than normal for this location.
3–4°F Below Normal
The average maximum temperature was 3–4°F colder than normal for this location.
1–3°F Below Normal
The average maximum temperature was 1–3°F colder than normal for this location.
0–1°F Below Normal
The average maximum temperature was 0–1°F colder than normal for this location.
0–1°F Above Normal
The average maximum temperature was 0–1°F warmer than normal for this location.
1–3°F Above Normal
The average maximum temperature was 1–3°F warmer than normal for this location.
3–4°F Above Normal
The average maximum temperature was 3–4°F warmer than normal for this location.
4–6°F Above Normal
The average maximum temperature was 4–6°F warmer than normal for this location.
6–8°F Above Normal
The average maximum temperature was 6–8°F warmer than normal for this location.
>8°F Above Normal
The average maximum temperature was more than 8°F warmer than normal for this location.
This map shows the average maximum daily temperature (°F) for the last 7 days. Blue hues indicate cooler temperatures, while red hues indicate warmer temperatures.
This map shows the average maximum daily temperature for the past 7 days compared to the historical average (1991–2020) for the same 7 days. Negative values (blue hues) indicate colder than normal temperatures, and positive values (red hues) indicate warmer than normal temperatures.
This map shows the average maximum daily temperature for the past 30 days compared to the historical average (1991–2020) for the same 30 days. Negative values (blue hues) indicate colder than normal temperatures, and positive values (red hues) indicate warmer than normal temperatures.
Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.
Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.
Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.
Air temperature can have wide-ranging effects on natural processes. Warmer air temperatures increase evapotranspiration—which is the combination of evaporation from the soil and bodies of water and transpiration from plants—and lower soil moisture.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreAir temperature can have wide-ranging effects on natural processes. Warmer air temperatures increase evapotranspiration—which is the combination of evaporation from the soil and bodies of water and transpiration from plants—and lower soil moisture.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreAir temperature can have wide-ranging effects on natural processes. Warmer air temperatures increase evapotranspiration—which is the combination of evaporation from the soil and bodies of water and transpiration from plants—and lower soil moisture.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn More8–14 Day Precipitation & Temperature Outlooks
Probability of Below-Normal Precipitation
33%–40% Chance of Below Normal
There is an 33%–40% chance of below-normal precipitation during this period.
40%–50% Chance of Below Normal
There is an 40%–50% chance of below-normal precipitation during this period.
50%–60% Chance of Below Normal
There is an 50%–60% chance of below-normal precipitation during this period.
60%–70% Chance of Below Normal
There is an 60%–70% chance of below-normal precipitation during this period.
70%–80% Chance of Below Normal
There is an 70%–80% chance of below-normal precipitation during this period.
80%–90% Chance of Below Normal
There is an 80%–90% chance of below-normal precipitation during this period.
>90% Chance of Below Normal
There is a >90% chance of below-normal precipitation during this period.
Probability of Above-Normal Precipitation
33%–40% Chance of Above Normal
There is an 33%–40% chance of above-normal precipitation during this period.
40%–50% Chance of Above Normal
There is an 40%–50% chance of above-normal precipitation during this period.
50%–60% Chance of Above Normal
There is an 50%–60% chance of above-normal precipitation during this period.
60%–70% Chance of Above Normal
There is an 60%–70% chance of above-normal precipitation during this period.
70%–80% Chance of Above Normal
There is an 70%–80% chance of above-normal precipitation during this period.
80%–90% Chance of Above Normal
There is an 80%–90% chance of above-normal precipitation during this period.
>90% Chance of Above Normal
There is a >90% chance of above-normal precipitation during this period.
Near-Normal
Odds favor near-normal precipitation during this period.
Probability of Below-Normal Temperatures
33%–40% Chance of Below Normal
There is an 33%–40% chance of below-normal temperatures during this period.
40%–50% Chance of Below Normal
There is an 40%–50% chance of below-normal temperatures during this period.
50%–60% Chance of Below Normal
There is an 50%–60% chance of below-normal temperatures during this period.
60%–70% Chance of Below Normal
There is an 60%–70% chance of below-normal temperatures during this period.
70%–80% Chance of Below Normal
There is an 70%–80% chance of below-normal temperatures during this period.
80%–90% Chance of Below Normal
There is an 80%–90% chance of below-normal temperatures during this period.
>90% Chance of Below Normal
There is a >90% chance of below-normal temperatures during this period.
Probability of Above-Normal Temperatures
33%–40% Chance of Above Normal
There is an 33%–40% chance of above-normal temperatures during this period.
40%–50% Chance of Above Normal
There is an 40%–50% chance of above-normal temperatures during this period.
50%–60% Chance of Above Normal
There is an 50%–60% chance of above-normal temperatures during this period.
60%–70% Chance of Above Normal
There is an 60%–70% chance of above-normal temperatures during this period.
70%–80% Chance of Above Normal
There is an 70%–80% chance of above-normal temperatures during this period.
80%–90% Chance of Above Normal
There is an 80%–90% chance of above-normal temperatures during this period.
>90% Chance of Above Normal
There is a >90% chance of above-normal temperatures during this period.
Near-Normal
Odds favor near-normal temperatures during this period.
This map shows the probability (percent chance) of above-normal, near-normal, or below-normal precipitation 8 to 14 days in the future.
This map shows the probability (percent chance) of above-normal, near-normal, or below-normal temperature 8 to 14 days in the future.
The Climate Prediction Center updates their 8–14 day outlooks daily.
The Climate Prediction Center updates their 8–14 day outlooks daily.
Drought is defined as the lack of precipitation over an extended period of time, usually for a season or more, that results in a water shortage. Changes in precipitation can substantially disrupt crops and livestock, influence the frequency and intensity of severe weather events, and affect the quality and quantity of water available for municipal and industrial use.
Learn MoreFlash drought is the rapid onset or intensification of drought. Unlike slow-evolving drought, which is caused by a decline in precipitation, flash drought occurs when low precipitation is accompanied by abnormally high temperatures, high winds, and/or changes in radiation. These sometimes-rapid changes can quickly raise evapotranspiration rates and remove available water from the landscape.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreAir temperature can have wide-ranging effects on natural processes. Warmer air temperatures increase evapotranspiration—which is the combination of evaporation from the soil and bodies of water and transpiration from plants—and lower soil moisture.
Learn MoreFlash drought is the rapid onset or intensification of drought. Unlike slow-evolving drought, which is caused by a decline in precipitation, flash drought occurs when low precipitation is accompanied by abnormally high temperatures, high winds, and/or changes in radiation. These sometimes-rapid changes can quickly raise evapotranspiration rates and remove available water from the landscape.
Learn MoreU.S. Drought Outlooks
Drought Is Predicted To...
Drought Persists
During this time period, NOAA's Climate Prediction Center predicts that drought conditions will persist.
Drought Improves
During this time period, NOAA's Climate Prediction Center predicts that existing drought conditions will improve (but not be removed).
Drought Is Removed
During this time period, NOAA's Climate Prediction Center predicts that drought will be removed.
Drought Develops
During this time period, NOAA's Climate Prediction Center predicts that drought will develop.
No Drought Present
According to NOAA's Climate Prediction Center, there is no drought, and is drought development is not predicted.
Drought Is Predicted To...
Drought Persists
During this time period, NOAA's Climate Prediction Center predicts that drought conditions will persist.
Drought Improves
During this time period, NOAA's Climate Prediction Center predicts that existing drought conditions will improve (but not be removed).
Drought Is Removed
During this time period, NOAA's Climate Prediction Center predicts that drought will be removed.
Drought Develops
During this time period, NOAA's Climate Prediction Center predicts that drought will develop.
No Drought Present
According to NOAA's Climate Prediction Center, there is no drought, and is drought development is not predicted.
The Monthly Drought Outlook predicts whether drought will develop, remain, improve, or be removed in the next calendar month.
The Seasonal Drought Outlook predicts whether drought will develop, remain, improve, or be removed in the next 3 months or so.
The Climate Prediction Center issues its Monthly Drought Outlooks on the last day of the calendar month.
The Climate Prediction Center issues its Seasonal Drought Outlooks on the third Thursday of each calendar month. Sometimes, the map is adjusted on the last day of the month to maintain consistency with the Monthly Drought Outlook.
Snow drought is a period of abnormally low snowpack for the time of year. Snowpack typically acts as a natural reservoir, providing water throughout the drier summer months. Lack of snowpack storage, or a shift in timing of snowmelt, can be a challenge for drought planning.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreDuring drought conditions, fuels for wildfire, such as grasses and trees, can dry out and become more flammable. Drought can also increase the probability of ignition and the rate at which fire spreads. Temperature, soil moisture, humidity, wind speed, and fuel availability (vegetation) are all factors that interact to influence the frequency of large wildfires.
Learn MoreSnow drought is a period of abnormally low snowpack for the time of year. Snowpack typically acts as a natural reservoir, providing water throughout the drier summer months. Lack of snowpack storage, or a shift in timing of snowmelt, can be a challenge for drought planning.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreDuring drought conditions, fuels for wildfire, such as grasses and trees, can dry out and become more flammable. Drought can also increase the probability of ignition and the rate at which fire spreads. Temperature, soil moisture, humidity, wind speed, and fuel availability (vegetation) are all factors that interact to influence the frequency of large wildfires.
Learn MoreHistorical Conditions for Sonoma County
U.S. Drought Monitor
D0 - Abnormally Dry
Abnormally Dry (D0) indicates a region that is going into or coming out of drought, according to the U.S. Drought Monitor. View typical impacts by state.
D1 – Moderate Drought
Moderate Drought (D1) is the first of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
D2 – Severe Drought
Severe Drought (D2) is the second of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
D3 – Extreme Drought
Extreme Drought (D3) is the third of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
D4 – Exceptional Drought
Exceptional Drought (D4) is the most intense drought category, according to the U.S. Drought Monitor. View typical impacts by state.
The U.S. Drought Monitor (2000–present) depicts the location and intensity of drought across the country. Every Thursday, authors from NOAA, USDA, and the National Drought Mitigation Center produce a new map based on their assessments of the best available data and input from local observers. The map uses five categories: Abnormally Dry (D0), showing areas that may be going into or are coming out of drought, and four levels of drought (D1–D4). Learn more.
Dry Conditions
D4 (SPI of -2.0 or less)
The 9-month Standardized Precipitation Index (SPI) value for this location is -2.0 or less, indicating exceptional drought (D4) conditions.
D3 (SPI of -1.9 to -1.6)
The Standardized Precipitation Index (SPI) value for this location is between -1.9 to -1.6, indicating extreme drought (D3) conditions.
D2 (SPI of -1.5 to -1.3)
The Standardized Precipitation Index (SPI) value for this location is between -1.5 to -1.3, indicating severe drought (D2) conditions.
D1 (SPI of -1.2 to -0.8)
The Standardized Precipitation Index (SPI) value for this location is between -1.2 to -0.8, indicating moderate drought (D1) conditions.
D0 (SPI of -0.7 to -0.5)
The Standardized Precipitation Index (SPI) value for this location is between -0.7 to -0.5, indicating abnormally dry (D0) conditions.
Wet Conditions
W0 (SPI of 0.5 to 0.7)
The Standardized Precipitation Index (SPI) value for this location is between 0.5 to 0.7, indicating abnormally wet (W0) conditions.
W1 (SPI of 0.8 to 1.2)
The Standardized Precipitation Index (SPI) value for this location is between 0.8 to 1.2, indicating moderate wet (W1) conditions.
W2 (SPI of 1.3 to 1.5)
The Standardized Precipitation Index (SPI) value for this location is between 1.3 to 1.5, indicating severe wet (W2) conditions.
W3 (SPI of 1.6 to 1.9)
The Standardized Precipitation Index (SPI) value for this location is between 1.6 to 1.9, indicating extreme wet (W3) conditions.
W4 (SPI of 2.0 or more)
The Standardized Precipitation Index (SPI) value for this location is 2.0 or greater, indicating exceptional wet (W4) conditions.
In paleoclimatology, proxy climate data (e.g., tree rings, ocean sediments) can allow us to reconstruct past climate conditions before we had widespread instrumental records. The Living Blended Drought Atlas, shown here, estimates average drought conditions each summer (June–August) as far back as the year 0 by combining tree-ring reconstructions and instrumental records. Red hues indicate drier conditions, while blue hues indicate wetter conditions.
Dry Conditions
D4 (PMDI of -5.0 or less)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -5.0 or less, indicating exceptional drought (D4) conditions.
D3 (PMDI of -4.9 to -4.0)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -4.9 to -4.0, indicating extreme drought (D3) conditions.
D2 (PMDI of -3.9 to -3.0)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -3.9 to -3.0, indicating severe drought (D2) conditions.
D1 (PMDI of -2.9 to -2.0)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -2.9 to -2.0, indicating moderate drought (D1) conditions.
D0 (PMDI of -1.9 to -1.0)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -1.9 to -1.0, indicating abnormally dry (D0) conditions.
Wet Conditions
W0 (PMDI of 1.0 to 1.9)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 1.0 to 1.9, indicating abnormally wet (W0) conditions.
W1 (PMDI of 2.0 to 2.9)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 2.0 to 2.9, indicating moderate wet (W1) conditions.
W2 (PMDI of 3.0 to 3.9)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 3.0 to 3.9, indicating severe wet (W2) conditions.
W3 (PMDI of 4.0 to 4.9)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 4.0 to 4.9, indicating extreme wet (W3) conditions.
W4 (PMDI of 5.0 or greater)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 5.0 or greater, indicating exceptional wet (W4) conditions.
Tree-rings are used to extend the instrumental record of drought to over 2000 years. The Living Blended Drought Product (LBDP) is a recalibrated data series of June-July-August Palmer Modified Drought Index (PMDI) values in the lower 48 U.S. states. This dataset blends tree-ring reconstructions and instrumental data to estimate the average summer PMDI values, which extend over 2000 years in some parts of the U.S. Learn more.
people in Sonoma County are affected by drought
of people in Sonoma County are affected by drought
driest October on record, over the past 130 years
wettest year to date over the past 130 years (January-October 2024)