Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Climatic moisture categories for the SPI and SPEI2.
| Climatic moisture categories | SPI or SPEI |
|---|---|
| Extremely wet | ≥ 2.0 |
| Severely wet | 1.5 to 1.99 |
| Moderately wet | 1.0 to 1.49 |
| Normal | 0.99 to − 0.99 |
| Moderate drought | − 1.0 to − 1.49 |
| Severe drought | − 1.5 to − 1.99 |
| Extreme drought | ≤ − 2.0 |
