Idaho weather in September: Statewide normals and every place, NOAA 1991-2020
In September, Idaho's statewide normal high is 71°F and normal low 42°F; normal highs run from 59°F in Mullan to 86°F in Glenns Ferry (NOAA 1991-2020 normals).
- Statewide normal high
- 71°FSeptember, 1991-2020
- Statewide normal low
- 42°FSeptember, 1991-2020
- Statewide normal precipitation
- 1.10 inSeptember
- Warmest place
- 86°Fnormal high, Glenns Ferry
- Coolest place
- 59°Fnormal high, Mullan
Where is Idaho warmest and wettest in September?
Glenns Ferry has the warmest September afternoons (86°F) and Mullan the coolest (59°F). Soda Springs gets the most precipitation (1.81 in) and Grand View the least (0.24 in).
Statewide, September averaged 57.2°F in 2021, 60.8°F in 2022, 56.6°F in 2023, 59.4°F in 2024, 60.7°F in 2025, against a 1991-2020 normal of 56.4°F.
| Place | High | Low | Precip. | Snow |
|---|---|---|---|---|
| Boise | 80°F | 53°F | 0.43 | 0.0 |
| Nampa | 81°F | 47°F | 0.36 | 0.0 |
| Idaho Falls | 75°F | 41°F | 0.97 | – |
| Pocatello | 77°F | 42°F | 0.89 | 0.0 |
| Coeur d'Alene | 74°F | 48°F | 0.81 | – |
| Twin Falls | 76°F | 47°F | 0.53 | – |
| Rexburg | 73°F | 42°F | 0.78 | – |
| Lewiston | 80°F | 52°F | 0.60 | 0.0 |
| Moscow | 76°F | 40°F | 1.01 | 0.0 |
| Mountain Home | 82°F | 48°F | – | – |
| Jerome | 78°F | 49°F | 0.33 | – |
| Blackfoot | 75°F | 46°F | 0.97 | 0.0 |
| Burley | 77°F | 45°F | 0.66 | – |
| Sandpoint | 72°F | 42°F | 1.41 | 0.0 |
| Emmett | 80°F | 48°F | 0.42 | 0.0 |
| Payette | 80°F | 50°F | 0.85 | – |
| Preston | 77°F | 43°F | 1.48 | 0.0 |
| Weiser | 81°F | 49°F | 0.40 | – |
| Rigby | 75°F | 46°F | 1.09 | – |
| American Falls | 77°F | 46°F | 0.81 | – |
| Buhl | 77°F | 49°F | 0.44 | – |
| McCall | 71°F | 38°F | 0.96 | – |
| St. Anthony | 73°F | 41°F | 1.06 | – |
| Grangeville | 73°F | 45°F | 1.30 | 0.0 |
| Ketchum | 69°F | 36°F | 1.01 | 0.0 |
| Salmon | 74°F | 41°F | 0.79 | 0.0 |
| Soda Springs | 74°F | 36°F | 1.81 | – |
| Homedale | 81°F | 46°F | 0.41 | – |
| Bonners Ferry | 73°F | 45°F | 1.02 | 0.0 |
| Bellevue | 76°F | 45°F | 0.84 | – |
| St. Maries | 75°F | 44°F | 1.04 | 0.0 |
| Kellogg | 73°F | 41°F | 1.32 | 0.0 |
| Sugar City | 74°F | 38°F | – | – |
| Fort Hall | 76°F | 41°F | 0.83 | 0.0 |
| Driggs | 73°F | 38°F | 1.47 | – |
| Malad City | 78°F | 41°F | 1.23 | – |
| Parma | 82°F | 46°F | 0.64 | 0.0 |
| Aberdeen | 76°F | 40°F | 0.83 | 0.0 |
| Shoshone | 81°F | 51°F | 0.46 | – |
| Paul | 74°F | 45°F | 0.61 | – |
| Glenns Ferry | 86°F | 46°F | 0.44 | – |
| Kamiah | 80°F | 46°F | 1.15 | 0.0 |
| Plummer | 73°F | 44°F | 1.02 | – |
| Cascade | 73°F | 40°F | 0.99 | 0.0 |
| Hagerman | 81°F | 44°F | 0.42 | – |
| Ashton | 73°F | 42°F | 1.17 | 0.0 |
| Council | 80°F | 45°F | 0.95 | – |
| Grace | 73°F | 41°F | 1.38 | – |
| Challis | 75°F | 42°F | 0.85 | – |
| Cottonwood | 72°F | 49°F | 1.06 | 0.1 |
| Arco | 75°F | 41°F | 0.66 | 0.0 |
| Oakley | 77°F | 47°F | 1.08 | 0.0 |
| Hazelton | 78°F | 45°F | 0.50 | – |
| McCammon | 76°F | 42°F | 1.24 | 0.0 |
| Wallace | 71°F | 44°F | 1.61 | 0.0 |
| Potlatch | 74°F | 42°F | 0.95 | 0.0 |
| Mullan | 59°F | 44°F | 1.65 | – |
| New Meadows | 75°F | 33°F | 1.01 | – |
| Downey | 77°F | 41°F | 1.44 | – |
| Kooskia | 77°F | 45°F | – | – |
| Idaho City | 77°F | 36°F | 0.77 | – |
| Dubois | 75°F | 45°F | 0.89 | 0.0 |
| Pierce | 73°F | 36°F | 1.61 | 0.0 |
| Fairfield | 74°F | 40°F | 0.70 | – |
| Mackay | 72°F | 40°F | 0.77 | – |
| Richfield | 77°F | 43°F | 0.49 | 0.0 |
| Nezperce | 71°F | 42°F | 0.95 | 0.0 |
| Grand View | 83°F | 47°F | 0.24 | – |
| Riggins | 80°F | 45°F | 1.16 | 0.0 |
| Lava Hot Springs | 75°F | 41°F | 1.43 | – |
| Winchester | 70°F | 42°F | 1.05 | 0.0 |
| Cambridge | 80°F | 44°F | 0.57 | – |
| Garden Valley | 79°F | 39°F | 0.85 | 0.0 |
| Swan Valley | 75°F | 37°F | 1.55 | – |
| Tetonia | 69°F | 38°F | 1.50 | – |
| Elk City | 74°F | 32°F | 1.61 | 0.0 |
| Castleford | 76°F | 44°F | 0.50 | – |
| Island Park | 68°F | 32°F | 1.66 | – |
| Malta | 77°F | 40°F | 0.88 | 0.0 |
| Stanley | 70°F | 31°F | 1.01 | – |
| Leadore | 71°F | 34°F | – | – |
| Minidoka | 78°F | 44°F | 0.68 | 0.0 |
| Hamer | 78°F | 39°F | 0.63 | 0.0 |
| Lowman | 76°F | 37°F | – | – |
| Bruneau | 84°F | 49°F | 0.26 | – |
| Arrowrock Dam | 80°F | 49°F | – | – |
| Bayview Model Basin | 69°F | 42°F | 0.99 | 0.0 |
| Bern | 74°F | 37°F | 1.35 | 0.1 |
| Boise Lucky Peak Dam | 81°F | 50°F | 0.52 | – |
| Brownlee Dam | 83°F | 55°F | 0.51 | – |
| Cabinet Gorge | 71°F | 44°F | 1.52 | – |
| Chilly Barton Flat | 72°F | 37°F | 0.65 | 0.2 |
| Craters Of The Moon | 69°F | 38°F | 0.83 | 0.1 |
| Deadwood Lodge | 73°F | 32°F | 1.28 | – |
| Deer Flat Dam | 80°F | 49°F | 0.37 | – |
| Dixie | 67°F | 30°F | – | – |
| Dixie N | 65°F | 31°F | 1.40 | – |
| Dworshak Fish Hatchery | 80°F | 48°F | 0.87 | 0.0 |
| Elk River | 72°F | 40°F | 1.50 | – |
| Fenn Ranger Station | 78°F | 45°F | 1.62 | 0.0 |
| Gibbonsville #2 | 73°F | 38°F | – | – |
| Headquarters | 70°F | 35°F | 1.43 | 0.0 |
| Hill City (1 mi W) | 76°F | 37°F | 0.52 | – |
| Howe | 76°F | 39°F | 0.52 | 0.0 |
| Idaho Falls (46 mi W) | 76°F | 38°F | 0.66 | 0.0 |
| Idaho Falls - Kifi | 75°F | 45°F | 1.13 | – |
| Lifton Pumping Station | 70°F | 39°F | 1.09 | 0.1 |
| Lowell Three Rivers | 79°F | 48°F | 1.51 | – |
| Massacre Rocks State Park | 77°F | 43°F | 0.88 | – |
| May (2 mi SSE) | 76°F | 35°F | 0.89 | – |
| Middle Fork Lodge | 76°F | 39°F | 1.02 | 0.0 |
| Monteview | 75°F | 38°F | 0.62 | – |
| Murphy (10 mi W) | 76°F | 44°F | 0.56 | – |
| Murphy (Desert) Hot Springs | 77°F | 37°F | 0.88 | 0.0 |
| Ola | 81°F | 40°F | 0.54 | – |
| Picabo | 76°F | 37°F | 0.58 | 0.0 |
| Porthill (1 mi SW) | 74°F | 42°F | 1.06 | – |
| Powell | 71°F | 37°F | – | – |
| Prichard (3 mi ESE) | 73°F | 37°F | 1.71 | – |
| Priest River Experiment Station | 72°F | 39°F | 1.30 | 0.0 |
| Red River Ranger Station | 73°F | 33°F | – | – |
| Rexburg BYU Idaho | 74°F | 43°F | 1.04 | – |
| Shoup | 77°F | 45°F | – | – |
| Silver City (5 mi W) | 72°F | 49°F | – | – |
| Small (6 mi N) | 71°F | 41°F | 0.97 | – |
| Swan Falls Powerhouse | 83°F | 53°F | 0.27 | – |
| Taylor Ranch | 76°F | 42°F | 1.10 | 0.0 |
| Twin Falls-KMVT | 80°F | 47°F | 0.33 | – |
| Warren | 69°F | 30°F | – | – |
| Yellowpine | 76°F | 37°F | 1.33 | – |
| Yellowpine Bar | 81°F | 45°F | 1.36 | 0.0 |
Source: NOAA NCEI nClimDiv statewide normals; NOAA NCEI 1991-2020 monthly normals for each station.