Frost dates in Lewis and Clark County, Montana
The average last spring frost in Lewis and Clark County falls May 9 to Jun 12 and the average first fall frost Sep 8 to Sep 30, depending on the ZIP code (50% odds, 32°F, NOAA 1991–2020 normals). USDA hardiness zone 4b to 5a. Places: Augusta, Canyon Creek, Helena, Helena Valley Northeast, Helena West Side, Lincoln. Pick a ZIP for 10% and 90% odds, soil temperature and the 7-day freeze forecast.
| ZIP | Place | Last spring frost | First fall frost | Zone |
|---|---|---|---|---|
| 59410 | Augusta | Jun 12 | Sep 8 | 4b |
| 59601 | Helena | Jun 4 | Sep 14 | 4b |
| 59602 | Helena Valley Northeast | May 9 | Sep 30 | 4b |
| 59623 | Helena | May 9 | Sep 30 | 5a |
| 59625 | Helena | May 9 | Sep 30 | 4b |
| 59633 | Canyon Creek | Jun 4 | Sep 14 | 4b |
| 59635 | Spokane Creek | May 9 | Sep 30 | 5a |
| 59636 | Helena West Side | May 9 | Sep 30 | 4b |
| 59639 | Lincoln | May 21 | Sep 15 | 4b |
| 59640 | Marysville | Jun 4 | Sep 14 | 4b |
| 59648 | Milford Colony | May 21 | Sep 15 | 4b |
Nearby counties
Powell County Broadwater County Jefferson County Cascade County Granite County Silver Bow County
All Montana counties · Download Montana frost dates (CSV)
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