Helmville, MT frost dates
Last spring frostAny monthno frost-free season
Freezing nights247 / yrat or below 32°F
Hardiness zone5aZone 5a
Gardening where frost is possible all year
The weather station nearest Helmville, MT records freezing temperatures in every month often enough that NOAA cannot define a frost-free season. Gardening is still possible — it just means planning for frost at any time:
- Grow fast, cold-tolerant crops: Radishes, Lettuce, Spinach, Kale, Peas, Potatoes, Swiss Chard, Garlic.
- Plant once the soil can be worked — usually late spring to early summer at high elevation — and keep row covers ready for clear, still nights.
- Use season extension: cold frames, low tunnels, wall-of-water cloches or a greenhouse turn a few frost-free weeks into a real season.
- Frost-tender crops (tomatoes, squash, beans) need protection all season; choose the earliest varieties you can find.
How Helmville compares
- Nearby Missoula, MT, 83 km away, has a regular frost season (last frost May 10), a reminder of how much elevation and distance from the coast matter.
About these dates
Based on 1991–2020 NOAA climate normals for the Ovando 9 Sse, MT weather station, 11 km away (elevation 4,324 ft (1,318 m)).
Frost dates near Helmville
- Ovando frost any month
- Lincoln frost any month
- Gold Creek frost any month
- Garrison frost any month
- Drummond frost any month
- Hall frost any month
- Avon Jun 9 · Sep 8
- Marysville Jun 4 · Sep 14
- Canyon Creek Jun 4 · Sep 14
- Deer Lodge frost any month
Frequently asked questions
When is the last frost in Helmville, MT?
Helmville, MT can freeze in any month, so there is no reliable last frost date. The nearest NOAA station averages 247 nights a year at or below 32°F.
What can I grow in Helmville, MT?
Fast, cold-tolerant crops such as radishes, lettuce, spinach, kale, peas and potatoes, ideally under row covers, cold frames or a greenhouse. Frost-tender crops like tomatoes need protection all season.