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The Drought.gov team reformats data from multiple partners into web- and GIS-ready formats, which we use throughout Drought.gov. These data, hosted on Google Cloud Storage, are free for all to download or reference directly from their web applications.

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Dataset Name

USDA Disaster Designations

Update Schedule
Updates Weekly
Last Update
12/17/24

The Secretary of Agriculture is authorized to designate counties as disaster areas to make emergency loans (EM) available to producers suffering losses in those counties and in counties that are contiguous to a designated county. In addition to EM eligibility, other emergency assistance programs, such as FSA disaster assistance programs, have historically used disaster designations as an eligibility trigger.

U.S. Department of Agriculture (USDA) drought disaster designation data were ingested from the USDA Disaster Designation Information page. USDA provides a list of counties, which was used to count the number of counties designated in a state.

Source(s)
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Dataset Name

Population in Drought (U.S. Drought Monitor)

Update Schedule
Updates Weekly on Thursdays
Last Update
12/17/24

Drought population percentages were ingested using U.S. Drought Monitor web services. The U.S. Drought Monitor provides an estimated population in drought using the most recent U.S. Census data. These estimates assume that the population of each county is distributed equally across that county and are not exact numbers.

Methodology (learn more via the U.S. Drought Monitor website):

"The population density for each county is determined by dividing the population of the county by the area of the county in square miles.To compute the population in drought statistics each week, this population density value is multiplied by the percent of the area in a given USDM category to determine the number of people living in the area of each USDM category. This is done for each county in the U.S. that is in drought. Once the county-level statistics are calculated, the numbers are aggregated up to the state level by summing the values for each county within the state. The state values are then aggregated to the national level."

Source(s)
Update Schedule

Current population in drought statistics for the U.S. Drought Monitor are updated weekly on Thursdays, with data valid through Tuesday at 7 a.m. Eastern.

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Dataset Name

Climate at a Glance: Monthly Precipitation Rankings

Update Schedule
Updates Monthly
Last Update
12/21/24

Monthly and year-to-date state-level precipitation ranks, precipitation totals, and departure from normal precipitation data were ingested from the NOAA National Centers for Environmental Information (NCEI) Climate at a Glance tool. Climate at a Glance was developed at the request of NOAA Headquarters for near real-time analysis of monthly temperature and precipitation data across the contiguous U.S. and intended for the study of climate variability. Data for the contiguous U.S. come from the U.S. Climate Divisional Database, which have data from 1895 to the present.

NCEI provides the rank data in XML, CSV, and JSON formats.

Source(s)
Update Schedule

Precipitation data are updated once a month with data for the previous month. View the future update schedule.

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Dataset Name

Climate at a Glance: Calendar Year to Date Precipitation Rankings

Update Schedule
Updates Monthly
Last Update
12/21/24

Monthly and year-to-date state-level precipitation ranks, precipitation totals, and departure from normal precipitation data were ingested from the NOAA National Centers for Environmental Information (NCEI) Climate at a Glance tool. Climate at a Glance was developed at the request of NOAA Headquarters for near real-time analysis of monthly temperature and precipitation data across the contiguous U.S. and intended for the study of climate variability. Data for the contiguous U.S. come from the U.S. Climate Divisional Database, which have data from 1895 to the present.

NCEI provides the rank data in XML, CSV, and JSON formats.

Source(s)
Update Schedule

Precipitation data are updated once a month with data for the previous month. View the future update schedule.

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Maps

Maps
Map
Dataset Name

U.S. Drought Monitor

Update Schedule
Updates Weekly
Last Update
12/17/24

U.S. Drought Monitor (USDM) data from the National Drought Mitigation Center were available in a GIS format. The USDM is jointly produced by NDMC, the National Oceanic and Atmospheric Administration, and the U.S. Department of Agriculture. The map is updated weekly on Thursday mornings, with data valid through Tuesday of that week.

Source(s)
Update Schedule

This map is released every Thursday morning, with data valid through Tuesday at 7am Eastern.

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Dataset Name

U.S. Drought Monitor 1-Week Change Map

Update Schedule
Data Valid
Last Update
12/17/24

U.S. Drought Monitor (USDM) data from the National Drought Mitigation Center were available in a GIS format. The USDM is jointly produced by the National Drought Mitigation Center, the National Oceanic and Atmospheric Administration, and the U.S. Department of Agriculture. The map is updated weekly on Thursday mornings, with data valid through Tuesday of that week.

Current weekly U.S. Drought Monito data is compared with the previous week to identify changes.

Source(s)
Update Schedule

U.S. Drought Monitor change maps are released every Thursday morning, with data valid through Tuesday at 7 am Eastern.

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Dataset Name

Short-Term Multi-Indicator Drought Index (MIDI)

Update Schedule
Data Valid
Last Update
12/15/24

The Short-Term Multi-Indicator Drought Index (MIDI) is an experimental blended product. It looks at current drought conditions across the U.S. by integrating several key short-term drought indices into one objective, computer-generated map. MIDI data were from Climate Engine were available in raster format. 

This product is based on methodology from the NOAA National Weather Service’s Climate Prediction Center. The short-term and long-term MIDIs are created using the Climate Engine tool, and apply Climate Prediction Center weighting ratios to the high-resolution gridMET gridded research dataset (reference period  1979–present). The data are updated every 5 days, with a delay of 4 to 5 days to allow for data collection and quality control.

The short-term MIDI combines the Palmer Drought Severity Index (PDSI), Palmer Z-Index, 1-month Standardized Precipitation Index (SPI), and 3-month SPI to approximate drought impacts from changes in precipitation and moisture over a short-term timeframe. This product is an example of current NIDIS-funded research. Learn more.

Source(s)
Update Schedule

The drought indices used in this map are based on the GridMET dataset and use a reference period of 1979–present. This map is updated every 5 days, with a delay of 4 to 5 days to allow for data collection and quality control.

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Dataset Name

Long-Term Multi-Indicator Drought Index (MIDI)

Update Schedule
Data Valid
Last Update
12/15/24

The Long-Term Multi-Indicator Drought Index (MIDI) is an experimental blended product. It looks at current drought conditions across the U.S. by integrating several key long-term drought indices into one objective, computer-generated map. MIDI data were from Climate Engine were available in raster format. 

This product is based on methodology from the NOAA National Weather Service’s Climate Prediction Center. The short-term and long-term MIDIs are created using the Climate Engine tool, and apply Climate Prediction Center weighting ratios to the high-resolution gridMET gridded research dataset (reference period  1979–present). The data are updated every 5 days, with a delay of 4 to 5 days to allow for data collection and quality control. 

The long-term MIDI combines the Palmer Drought Severity Index (PDSI), Palmer Z-Index, 180-day Standardized Precipitation Index (SPI), 1-year SPI, 2-year SPI, and 5-year SPI to approximate drought impacts from changes in precipitation and moisture over a long-term timeframe. This product uses the same percentile category ranges as the U.S. Drought Monitor.

This product is an example of current NIDIS-funded research. Learn more.

Source(s)
Update Schedule

The drought indices used in this map are based on the GridMET dataset and use a reference period of 1979–present. This map is updated every 5 days, with a delay of 4 to 5 days to allow for data collection and quality control.

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California Current Conditions

A number of physical indicators are important for monitoring drought, such as precipitation & temperature, water supply (e.g., streamflow, reservoirs), and soil moisture. Learn more about monitoring drought.

Map Cards
Map
Dataset Name

Precipitation Conditions: Last 7 Days (gridMET, NLDAS)

Update Schedule
Data Valid
Last Update
12/18/24

The gridMET and NLDAS precipitation datasets from Climate Engine were available in raster format. Precipitation data update daily but are delayed from the current day by 3 to 4 days to allow for data collection and quality control.

Source(s)
Update Schedule

Precipitation data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

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Dataset Name

Precipitation 30-day % of Normal (gridMET, NLDAS)

Update Schedule
Data Valid
Last Update
12/18/24

The GridMET and NLDAS precipitation datasets from Climate Engine were available in raster format.  Precipitation data update daily but are delayed from the current day by 3 to 4 days to allow for data collection and quality control.

Source(s)
Update Schedule

Precipitation data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

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Dataset Name

Precipitation 60-day % of Normal (gridMET, NLDAS)

Update Schedule
Data Valid
Last Update
12/18/24

The GridMET and NLDAS precipitation datasets from Climate Engine were available in raster format.  Precipitation data update daily but are delayed from the current day by 3 to 4 days to allow for data collection and quality control.

Source(s)
Update Schedule

Precipitation data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

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Map
Dataset Name

Temperature: 7-Day Average Maximum (gridMET, PRISM)

Update Schedule
Data Valid
Last Update
12/18/24

The GridMET and PRISM temperature datasets from Climate Engine were available in raster format. Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

Source(s)
Update Schedule

Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

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Map
Dataset Name

Maximum Temperature: 7-Day Departure from Normal (gridMET, PRISM)

Update Schedule
Data Valid
Last Update
12/18/24

The GridMET and PRISM temperature datasets from Climate Engine were available in raster format. Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

Source(s)
Update Schedule

Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

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Map
Dataset Name

Maximum Temperature: 30-Day Departure from Normal (gridMET, PRISM)

Update Schedule
Data Valid
Last Update
12/18/24

The GridMET and PRISM temperature datasets from Climate Engine were available in raster format. Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

Source(s)
Update Schedule

Temperature data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.

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Dataset Name

USGS Streamflow Conditions

Update Schedule
Data Valid
Last Update
12/20/24

Streamflow data were available in a GIS format from the U.S. Geological Survey (USGS) WaterWatch. 

Source(s)
Update Schedule

This map updates daily on Drought.gov. View the most recent real-time streamflow data via USGS.

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Dataset Name

USGS Streamflow Conditions: 7-Day Average

Update Schedule
Data Valid
Last Update
12/20/24

Streamflow data were available in a GIS format from the U.S. Geological Survey (USGS) WaterWatch. 

Source(s)
Update Schedule

This map updates daily on Drought.gov. View the most recent real-time streamflow data via USGS.

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Dataset Name

USGS Streamflow Conditions: 28-Day Average

Update Schedule
Data Valid
Last Update
12/20/24

Streamflow data were available in a GIS format from the U.S. Geological Survey (USGS) WaterWatch. 

Source(s)
Update Schedule

This map updates daily on Drought.gov. View the most recent real-time streamflow data via USGS.

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Dataset Name

NASA SPoRT-LIS 0-100 cm Soil Moisture Percentile

Update Schedule
Data Valid
Last Update
12/21/24

NASA’s Short-term Prediction and Transition Center – Land Information System (SPoRT-LIS) provides high-resolution (about 3-km) gridded soil moisture products in real-time to support regional and local modeling and improve situational awareness. The 0–100 cm soil moisture percentile data has shown to be a utility for drought monitoring. The near-surface (0–10 cm) layer responds quickly to heavy precipitation and rapidly drying events. In deeper layers, soil moisture evolves more slowly and has demonstrated greater utility overall for drought monitoring purposes since drought evolves typically on timescales of weeks to years. 

The 0–100 cm soil moisture percentiles use a 1981–2013 soil moisture climatology.

Soil moisture data from NASA Short-term Prediction Research and Transition Center (SPoRT) were available in raster format.

Source(s)
Update Schedule

This map updates daily with data from NASA's Short-term Prediction and Transition Center – Land Information System (SPoRT-LIS).

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Dataset Name

Crop-CASMA: Sub-9km Soil Moisture Anomaly

Update Schedule
Data Valid
Last Update
12/16/24

Soil moisture data from Crop-CASMA were available in GeoTIFF format. GIS software used the GeoTIFF format to create the map tiles used on Drought.gov.

Source(s)

NASA, USDA, George Mason University

Update Schedule

Data are updated daily, with a 3-day delay.

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Outlooks & Forecasts for California

Predicting drought in California depends on the ability to forecast precipitation and temperature within the context of complex climate interactions. View more outlooks & forecasts.

Map Cards
Map
Data Valid: Start Date
+0 days
Data Valid: End Date
+7 days
Dataset Name

Quantitative Precipitation Forecast: Day 1–7

Last Update
12/20/24

Produced by the National Weather Service's Weather Prediction Center, this Quantitative Precipitation Forecast shows the amount of liquid precipitation expected to fall over the next 7 days. (In the case of snow or ice, the forecast represents the amount of liquid that will be measured when the precipitation is melted.) Precipitation amounts can vary significantly over short distances, especially when thunderstorms occur, so the Quantitative Precipitation Forecast is defined as the expected "areal average" (on a 20 x 20 km grid) in inches. Learn more.

Quantitative Precipitation Forecast (QPF) data were available in a GIS format from the National Weather Service's Weather Prediction Center. The QPF maps on Drought.gov are updated daily and are valid from 12z (7 a.m. Eastern) that day.

Source(s)
Update Schedule

The Quantitative Precipitation Forecast maps on Drought.gov are updated once a day and are valid from 7 a.m. Eastern that day.

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Data Valid: Start Date
+8 days
Data Valid: End Date
+14 days
Dataset Name

CPC 8–14 Day Precipitation Outlook

Last Update
12/20/24

Temperature and precipitation data from NOAA's Climate Prediction Center were available in a GIS format. The 8–14 day outlook is updated daily.

Source(s)
Update Schedule

The Climate Prediction Center updates their 8–14 day outlooks daily.

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Data Valid: Start Date
+8 days
Data Valid: End Date
+14 days
Dataset Name

CPC 8–14 Day Temperature Outlook

Last Update
12/20/24

Temperature and precipitation data from NOAA's Climate Prediction Center were available in a GIS format.

Source(s)
Update Schedule

The Climate Prediction Center updates their 8–14 day outlooks daily.

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Data Valid: Start Date
first day of +1 month
Data Valid: End Date
last day of +1 month
Dataset Name

CPC U.S. Monthly Drought Outlook

Last Update
11/30/24

Drought outlooks from NOAA's Climate Prediction Center (CPC) were available in a GIS format. For more details about the current Monthly Drought Outlook map, read the latest monthly assessment from CPC.

Source(s)
Update Schedule

The Climate Prediction Center issues its Monthly Drought Outlooks on the last day of the calendar month.

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Data Valid: Start Date
+0 days
Data Valid: End Date
last day of +3 months
Dataset Name

CPC U.S. Seasonal Drought Outlook

Last Update
12/19/24

Drought outlooks from NOAA's Climate Prediction Center (CPC) were available in a GIS format. For more details about the current Seasonal Drought Outlook map, read the latest seasonal assessment from CPC.

Source(s)
Update Schedule

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.

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