U.S. Gridded Standardized Precipitation Index (SPI) from nClimGrid-Daily
National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI)
The Standardized Precipitation Index, or SPI, is a drought index that captures how observed precipitation deviates from the climatological average over a given time period. The U.S. Gridded Standardized Precipitation Index (SPI) from NOAA's National Centers for Environmental Information is derived from the nClimGrid-Daily dataset and includes timescales of 1, 2, and 3 weeks, as well as 1, 2, 3, 4, 6, 9, and 12 months.
The nClimGrid-Daily dataset is a gridded dataset, produced by NOAA's National Centers for Environmental Information, that includes area averages of daily maximum, minimum, and average temperatures and daily precipitation amounts for the contiguous United States from January 1, 1951 to the present. Data are derived from morning and midnight observations from the Global Historical Climatology Network-Daily (GHCNd) dataset, and contain processing techniques that address the spatial and temporal variations that affect the quality and homogeneity of the fields.
The Standardized Precipitation Index, or SPI, measures how observed precipitation deviates from average historical conditions for a given time range. SPI is used to estimate meteorological drought conditions. This map shows the SPI for the past month (30 days), based on NOAA precipitation data. Red, orange, and yellow hues indicate drier conditions, while green and blue hues indicate wetter conditions.
The Standardized Precipitation Index, or SPI, measures how observed precipitation deviates from average historical conditions for a given time range. SPI is used to estimate meteorological drought conditions. This map shows the SPI for the past 3 months (90 days), based on NOAA precipitation data. Red, orange, and yellow hues indicate drier conditions, while green and blue hues indicate wetter conditions.
The Standardized Precipitation Index, or SPI, measures how observed precipitation deviates from average historical conditions for a given time range. SPI is used to estimate meteorological drought conditions. This map shows the SPI for the past 6 months, based on NOAA precipitation data. Red, orange, and yellow hues indicate drier conditions, while green and blue hues indicate wetter conditions.
A drought index combines multiple drought indicators (e.g., precipitation, temperature, soil moisture) to depict drought conditions. For some products, like the U.S. Drought Monitor, authors combine their analysis of drought indicators with input from local observers. Other drought indices, like the Standardized Precipitation Index (SPI), use an objective calculation to describe the severity, location, timing, and/or duration of drought.
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 MoreA drought index combines multiple drought indicators (e.g., precipitation, temperature, soil moisture) to depict drought conditions. For some products, like the U.S. Drought Monitor, authors combine their analysis of drought indicators with input from local observers. Other drought indices, like the Standardized Precipitation Index (SPI), use an objective calculation to describe the severity, location, timing, and/or duration of drought.
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 MoreA drought index combines multiple drought indicators (e.g., precipitation, temperature, soil moisture) to depict drought conditions. For some products, like the U.S. Drought Monitor, authors combine their analysis of drought indicators with input from local observers. Other drought indices, like the Standardized Precipitation Index (SPI), use an objective calculation to describe the severity, location, timing, and/or duration of drought.
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 MoreDry Conditions
D4 - Exceptional Drought (SPI of -2.0 or less)
The Standardized Precipitation Index (SPI) value for this location is -2.0 or less. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -2.0 or less indicates Exceptional Drought (D4) conditions.
D3 - Extreme Drought (SPI of -1.9 to -1.6)
The Standardized Precipitation Index (SPI) value for this location is between -1.9 to -1.6. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.9 to -1.6 indicates Extreme Drought (D3) conditions.
D2 - Severe Drought (SPI of -1.5 to -1.3)
The Standardized Precipitation Index (SPI) value for this location is between -1.5 to -1.3. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.5 to -1.3 indicates Severe Drought (D2) conditions.
D1 - Moderate Drought (-1.2 to -0.8)
The Standardized Precipitation Index (SPI) value for this location is between -1.2 to -0.8. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.2 to -0.8 indicates Moderate Drought (D1) conditions.
D0 - Abnormally Dry (SPI of -0.7 to -0.5)
The Standardized Precipitation Index (SPI) value for this location is between -0.7 to -0.5. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -0.7 to -0.5 indicates Abnormally Dry (D0) conditions.
Wet Conditions
W0 (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 (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 (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 (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 (2.0 or more)
The Standardized Precipitation Index (SPI) value for this location is 2.0 or greater, indicating exceptional wet (W4) conditions.
Dry Conditions
D4 - Exceptional Drought (SPI of -2.0 or less)
The Standardized Precipitation Index (SPI) value for this location is -2.0 or less. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -2.0 or less indicates Exceptional Drought (D4) conditions.
D3 - Extreme Drought (SPI of -1.9 to -1.6)
The Standardized Precipitation Index (SPI) value for this location is between -1.9 to -1.6. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.9 to -1.6 indicates Extreme Drought (D3) conditions.
D2 - Severe Drought (SPI of -1.5 to -1.3)
The Standardized Precipitation Index (SPI) value for this location is between -1.5 to -1.3. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.5 to -1.3 indicates Severe Drought (D2) conditions.
D1 - Moderate Drought (-1.2 to -0.8)
The Standardized Precipitation Index (SPI) value for this location is between -1.2 to -0.8. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.2 to -0.8 indicates Moderate Drought (D1) conditions.
D0 - Abnormally Dry (SPI of -0.7 to -0.5)
The Standardized Precipitation Index (SPI) value for this location is between -0.7 to -0.5. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -0.7 to -0.5 indicates Abnormally Dry (D0) conditions.
Wet Conditions
W0 (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 (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 (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 (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 (2.0 or more)
The Standardized Precipitation Index (SPI) value for this location is 2.0 or greater, indicating exceptional wet (W4) conditions.
Dry Conditions
D4 - Exceptional Drought (SPI of -2.0 or less)
The Standardized Precipitation Index (SPI) value for this location is -2.0 or less. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -2.0 or less indicates Exceptional Drought (D4) conditions.
D3 - Extreme Drought (SPI of -1.9 to -1.6)
The Standardized Precipitation Index (SPI) value for this location is between -1.9 to -1.6. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.9 to -1.6 indicates Extreme Drought (D3) conditions.
D2 - Severe Drought (SPI of -1.5 to -1.3)
The Standardized Precipitation Index (SPI) value for this location is between -1.5 to -1.3. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.5 to -1.3 indicates Severe Drought (D2) conditions.
D1 - Moderate Drought (-1.2 to -0.8)
The Standardized Precipitation Index (SPI) value for this location is between -1.2 to -0.8. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -1.2 to -0.8 indicates Moderate Drought (D1) conditions.
D0 - Abnormally Dry (SPI of -0.7 to -0.5)
The Standardized Precipitation Index (SPI) value for this location is between -0.7 to -0.5. SPI values can be interpreted as the number of standard deviations by which the precipitation anomaly deviates from the long-term mean. An SPI of -0.7 to -0.5 indicates Abnormally Dry (D0) conditions.
Wet Conditions
W0 (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 (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 (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 (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 (2.0 or more)
The Standardized Precipitation Index (SPI) value for this location is 2.0 or greater, indicating exceptional wet (W4) conditions.
The Standardized Precipitation Index, or SPI, measures how observed precipitation deviates from average historical conditions for a given time range. SPI is used to estimate meteorological drought conditions. This map shows the SPI for the past month (30 days), based on NOAA precipitation data. Red, orange, and yellow hues indicate drier conditions, while green and blue hues indicate wetter conditions.
The Standardized Precipitation Index, or SPI, measures how observed precipitation deviates from average historical conditions for a given time range. SPI is used to estimate meteorological drought conditions. This map shows the SPI for the past 3 months (90 days), based on NOAA precipitation data. Red, orange, and yellow hues indicate drier conditions, while green and blue hues indicate wetter conditions.
The Standardized Precipitation Index, or SPI, measures how observed precipitation deviates from average historical conditions for a given time range. SPI is used to estimate meteorological drought conditions. This map shows the SPI for the past 6 months, based on NOAA precipitation data. Red, orange, and yellow hues indicate drier conditions, while green and blue hues indicate wetter conditions.
SPI data are updated daily, with a delay of 3–4 days.
SPI data are updated daily, with a delay of 3–4 days.
SPI data are updated daily, with a delay of 3–4 days.
A drought index combines multiple drought indicators (e.g., precipitation, temperature, soil moisture) to depict drought conditions. For some products, like the U.S. Drought Monitor, authors combine their analysis of drought indicators with input from local observers. Other drought indices, like the Standardized Precipitation Index (SPI), use an objective calculation to describe the severity, location, timing, and/or duration of drought.
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 MoreA drought index combines multiple drought indicators (e.g., precipitation, temperature, soil moisture) to depict drought conditions. For some products, like the U.S. Drought Monitor, authors combine their analysis of drought indicators with input from local observers. Other drought indices, like the Standardized Precipitation Index (SPI), use an objective calculation to describe the severity, location, timing, and/or duration of drought.
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 MoreA drought index combines multiple drought indicators (e.g., precipitation, temperature, soil moisture) to depict drought conditions. For some products, like the U.S. Drought Monitor, authors combine their analysis of drought indicators with input from local observers. Other drought indices, like the Standardized Precipitation Index (SPI), use an objective calculation to describe the severity, location, timing, and/or duration of drought.
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.
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Documentation
- nClimGrid-Daily Metadata
- User Guide: Provides basic information, references with additional information, and points of contact for the collection and processing of nClimGrid-Daily.
- Journal Article: Durre, Imke, Anthony Arguez, Carl J. Schreck III, Michael F. Squires, and Russell S. Vose. (2022.) Daily High-Resolution Temperature and Precipitation Fields for the Contiguous United States from 1951 to Present. Journal of Atmospheric and Oceanic Technology.
