From: Mapping the spatial and temporal variation of agricultural and meteorological drought using geospatial techniques, Ethiopia
SPI values
Drought category
 <  − 2.00 and less
Extreme drought
 − 1.50 to − 1.99
Severe drought
 − 1.00 to − 1.49
Moderate drought
0 to − 0.99 Near
Normal or mild drought
Above 0
No drought