County Location Page: Data & Maps
Below are all data sources used on the county-level location pages. Have questions about the data, maps, or statistics on Drought.gov? Email us at drought.portal@noaa.gov.
Looking for More Data?
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.
Statistics: Drought Numbers by County
Population in Drought
Sources: U.S. Drought Monitor
Data was ingested by the U.S. Drought Monitor web API and stored in a database on the web server. Learn more about how the National Drought Mitigation Center calculates U.S. Drought Monitor "population in drought" statistics.
Drought Rankings
Sources: NOAA National Centers for Environmental Information
County rank data were ingested from NOAA's National Centers for Environmental Information (NCEI) and joined with spatial data for mapping purposes.
Current Conditions
U.S. Drought Monitor
Maximum Temperature: 30-Day Departure from Normal
Sources: UC Merced, Climate Engine
The 30-day departure from normal maximum temperature (°F) shows the difference of the last 30 days from the usual conditions for the same time period averaged from 1991–2020. This map uses the gridMET and PRISM temperature datasets, which are delayed from the current day by 3 to 4 days to allow for data collection and quality control. Temperature data from Climate Engine were available in raster format.
* Currently, data are only available for the contiguous U.S.
Precipitation: 30-Day Percent of Normal
Sources: UC Merced, Climate Engine
The 30-day percent of normal precipitation map shows the difference of the last 30 days from the usual conditions for the same time period averaged from 1991–2020. This map uses the gridMET and NLDAS precipitation datasets, which are delayed from the current day by 3 to 4 days to allow for data collection and quality control. Precipitation data from Climate Engine were available in raster format.
* Currently, data are only available for the contiguous U.S.
Multi-Indicator Drought Index (MIDI)
Short-Term MIDI
Sources: UC Merced
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. 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.
* Currently, data are only available for the contiguous U.S.
Long-Term MIDI
Sources: UC Merced, Climate Engine
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. 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.
* Currently, data are only available for the contiguous U.S.
Agriculture by County
Crops and Livestock in Drought
Sources: USDA National Agricultural Statistics Service, U.S. Drought Monitor
County-level commodities data was collected from USDA agricultural censuses. County figures for field crops represent the total acres harvested within that county. County figures for livestock represent the total inventory within that county.
U.S. Drought Monitor (USDM) data from the National Drought Mitigation Center were available in a GIS format.
Agricultural Statistics
Source: USDA National Agricultural Statistics Service, U.S. Drought Monitor
GIS was used to aggregate the number of acres of a crop or inventory of livestock present in a county, according to 2017 data from the USDA National Agricultural Statistics Service. To calculate the acres of crops/inventory of livestock in drought, these values were multiplied by the percent area of the county in moderate (D1) to exceptional (D4) drought, according to the U.S. Drought Monitor.
This calculation makes several assumptions, including that crops and livestock are evenly distributed throughout a given county. Therefore, the crops and livestock in drought statistic is an estimation of crops and livestock in drought and not an exact value.
Water Supply by County
Daily Streamflow Conditions
Source: U.S. Geological Survey
Streamflow data were available in a GIS format from the U.S. Geological Survey's WaterWatch.
U.S. Drought Monitor (USDM) data from the National Drought Mitigation Center were available in a GIS format.
One-Month Precipitation Outlook
Source: Climate Prediction Center
Precipitation data from NOAA's Climate Prediction Center (CPC) were available in a GIS format.
U.S. Drought Monitor (USDM) data from the National Drought Mitigation Center were available in a GIS format.
Water Supply Statistics: Streamflow % Below Normal
Source: U.S. Geological Survey
Summary table information was ingested and parsed to provide statistics at the state level.
Water Supply Statistics: Precipitation % Below Normal
Source: Climate Prediction Center
Temperature and precipitation data from NOAA's Climate Prediction Center were available in a GIS format for the United States. GIS was used to extract data by state to generate state-level statistics.
Public Health by County
Social Vulnerability Index (SVI)
Sources: Centers for Disease Control and Prevention, U.S. Drought Monitor
SVI data were available in a GIS format at the county level from the Centers for Disease Control and Prevention (CDC).
U.S. Drought Monitor (USDM) data from the National Drought Mitigation Center were available in a GIS format.
National Weather Service Heat Warnings
Sources: National Weather Service, U.S. Drought Monitor
National Weather Service warnings were available in a GIS format. Data includes all NWS warnings. Heat related warnings (Excessive Heat Watches, Heat Advisories, and Excessive Heat Warnings) are extracted for the site.
U.S. Drought Monitor (USDM) data from the National Drought Mitigation Center were available in a GIS format.
Public Health Statistics: Wildfire by County
Source: National Interagency Fire Center
Active large wildfires were ingested from the National Interagency Fire Center (NFIC) FTP server. GIS was used to identify whether or not a county contained an active fire.
Public Health Statistics: Social Vulnerability Index Score
Source: Centers for Disease Control and Prevention
SVI data were available in a GIS format at the county level from the CDC.
Public Health Statistics: National Weather Service Heat Warnings
Source: National Weather Service
National Weather Service (NWS) warnings were available in a GIS format. Data includes all NWS warnings. Heat-related warnings were extracted for the site, and GIS was used to identify whether a heat warning was issued for a county.
Public Health Statistics: National Weather Service Air Quality Warnings
Source: National Weather Service
National Weather Service (NWS) warnings were available in a GIS format. Data includes all NWS warnings. Air quality warnings were extracted for the site, and GIS was used to identify whether an air quality warning was issued for a county.
Future Conditions
Evaporative Demand Drought Index (EDDI) Subseasonal Forecast
Source: UC Merced
Evaporative Demand Drought Index (EDDI) subseasonal forecast data were from the University of Idaho's THREDDS server in raster format.
U.S. Monthly and Seasonal Drought Outlooks
Source: Climate Prediction Center
Monthly and Seasonal Drought Outlooks from NOAA's Climate Prediction Center (CPC) were available in a GIS format.
Historical Conditions
U.S. Drought Monitor (2000 - Present)
Standardized Precipitation Index (1895 - Present)
Source: NOAA National Centers for Environmental Information
Standardized Precipitation Index (SPI) data was generated using nClimGrid 5km precipitation data. Monthly gridded SPI data was fitted into the U.S. Drought Monitor drought percentile categories. Categories were accumulated to provide statistical information at the CONUS, state, and county scales.
* Currently, data are only available for the contiguous U.S.
Paleoclimate Data (0 - 2017)
Source: NOAA National Centers for Environmental Information
Annual gridded paleoclimate Palmer Modified Drought Index (PMDI) data was fitted into the U.S. Drought Monitor drought percentile categories. Categories were accumulated to provide statistical information at the CONUS, state, and county scales.