Geodata and statistics / Humanitarian Data Exchange

Africa - Standardized Precipitation Index (SPI)

The Standardized Precipitation Index (SPI) is the globally recommended standard for characterizing meteorological drought. It quantifies observed precipitation as a standardized deviation from the long-term probability distribution function for a specific location and time scale. This dataset typically includes multiple time-scales (e.g., 1-month, 3-month, 6-month, 12-month) to capture different types of drought impacts, from immediate soil moisture deficits to long-term hydrological stress. Because SPI is normalized, it allows for safe comparisons between different climatic zones—allowing a w…