Average Rainfall for Idaho in September
The tables below give monthly averages for rainfall during September at cities, towns and parks in Idaho.
Each place has a total for the amount of precipitation it usually receives this month. There is also a count of the number of days with wet weather, when precipitation amounts to 0.01 inches (0.25 millimetres) or more.
The rainfall totals are averages based on weather data collected from 1991 to 2020 for the US National Centers for Environmental Information.
You can jump to a separate table for each region of the state: Eastern, Central, Southwestern and Northern Idaho.
Eastern Idaho
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 5 | Idaho Falls | 1.0 | 25 |
| 4 | Malad City | 1.2 | 31 |
| 5 | Pocatello | 1.2 | 30 |
| 6 | Preston | 1.5 | 38 |
| 4 | Saint Anthony | 1.1 | 27 |
Central Idaho
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 5 | Craters of the Moon Monument | 0.8 | 21 |
| 4 | Ketchum | 1.0 | 26 |
| 4 | Lake Walcott, Minidoka Dam | 0.7 | 17 |
| 6 | Middle Fork Lodge | 1.0 | 26 |
| 5 | Salmon | 0.8 | 20 |
| 6 | St. Maries | 1.0 | 26 |
| 7 | Stanley, Sawtooth Recreation Area | 1.0 | 26 |
| 3 | Twin Falls | 0.5 | 12 |
Southwestern Idaho
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 4 | Boise | 0.4 | 11 |
| 3 | Brownlee Reservoir Dam | 0.5 | 13 |
| 1 | Bruneau | 0.3 | 7 |
| 3 | Idaho City | 0.8 | 20 |
| 2 | Lake Lowell, Deer Flat Dam | 0.4 | 9 |
| 6 | McCall | 1.1 | 28 |
Northern Idaho
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 7 | Bonners Ferry | 1.0 | 26 |
| 6 | Coeur d’Alene | 0.8 | 21 |
| 7 | Elk City | 1.6 | 41 |
| 7 | Kellogg | 1.3 | 34 |
| 5 | Lewiston | 0.6 | 15 |
| 6 | Moscow | 1.0 | 26 |
| 6 | Porthill | 1.1 | 27 |
| 5 | Riggins | 1.2 | 29 |
| 7 | Sandpoint | 1.4 | 36 |
| 7 | Wallace | 1.6 | 41 |
Reference
NOAA National Centers for Environmental Information (NCEI). Climate Normals.