| SPI | SPI Category |
| ≥2.00 | Extremely Wet |
| 1.50 - 1.99 | Severely Wet |
| 1.00 - 1.49 | Moderately Wet |
| 0 - 0.99 | Mildly Wet |
| −0.99 - 0 | Mildly Drought |
| −1.49 - −1.00 | Moderate Drought |
| −1.99 - −1.50 | Severe Drought |
| ≤−2.00 | Extreme Drought |