The 3-month Standardized Precipitation Index (SPI-3) is a meteorological drought indicator to monitor precipitation anomalies over 3-month accumulation periods and is a proxy indicator for immediate impacts of droughts, such as reduced soil moisture, snowpack,...

The 1-month Standardized Precipitation Index (SPI-1) is an indicator used to monitor meteorological drought based on precipitation anomalies over 1-month accumulation periods. SPI-1 serves as a proxy indicator for immediate impacts of droughts such as reduced ...

The 6-month Standardized Precipitation Index (SPI-6) is a meteorological drought indicator to monitor precipitation anomalies over 6-month accumulation periods and is a proxy indicator for medium-term impacts, for example reduced stream flow and reservoir stor...