SPI value | Drought class | Probability (%) |
2 or more | Extremely wet | 2.3 |
1.5 to 1.99 | Very wet | 4.4 |
1.0 to 1.49 | Moderately wet | 9.2 |
0.99 to 0.99 | Near normal | 68.2 |
−1.0 to −1.49 | Moderately dry | 9.2 |
−1.5 to −1.99 | Severely dry | 4.4 |
−2 or less | Extremely dry | 2.3 |