SPI range | Drought category |
>2 | Extremely wet |
1.5 to 1.99 | Severely wet |
1.0 to 1.49 | Moderately wet |
0.99 to 0 | Mildly wet |
0 to -0.99 | Mild drought |
−1.0 to −1.49 | Moderate drought |
−1.5 to −1.99 | Severe drought |
<−2 | Extreme drought |