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