Frost dates for Great Falls, Montana
In a typical year, Great Falls’s last spring frost lands around May 6 and the first fall frost around Oct 1, a growing season of about 148 days. These are odds drawn from 30-year NOAA climate normals, not a promise. USDA zone 4b.
| Odds | Last spring frost | First fall frost |
|---|---|---|
| 10 percent | Apr 23 | Sep 17 |
| 50 percent | May 6 | Oct 1 |
| 90 percent | May 19 | Oct 16 |
A 10 percent year is an early year, a 90 percent year a late one. Frost-sensitive planting usually waits for the 90 percent side of the last-frost band.
Soil in Great Falls is typically around 70°F at 4 inches this time of year, estimated from the last two weeks of normal air temperatures.
Plantable now in Great Falls
- Bok choy (Toy Choi)
- Arugula (Astro)
- Mustard greens (Red Giant)
- Tatsoi (Tatsoi)
- Dill (Bouquet)
- Cilantro (Santo)
- Sweet alyssum (Snow Crystals)
- Mâche (Vit)
Timing comes from the same temperature engine the app uses, run against Great Falls’s normals for today.
Nearby cities
- Bozeman, MT (around May 26 to Sep 22)
- Missoula, MT (around May 10 to Oct 1)
- Billings, MT (around May 10 to Oct 1)
- Idaho Falls, ID (around May 9 to Oct 1)
- Spokane, WA (around Apr 26 to Oct 12)
Row & Bed is a plant reference built around your garden: your zone, your frost dates, your forecast, and a cited page for every variety in your beds.
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