Belt, MT frost dates
Last spring frostMay 22median date
First fall frostSep 23median date
Growing season124 daysfrost-free
Hardiness zone4bZone 4b
How Belt compares
- In 8 years out of 10, the last spring frost in Belt falls between May 7 and June 9, a 33-day window. The first fall frost falls between September 7 and October 6.
- The median last frost is 3 days later than the Montana median of May 19.
- Its 124-day growing season is longer than 45% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 14 days later than the zone 4b median of May 8. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4b chart.
- The weather station records an average of 165 nights a year at or below 32°F.
- Compared with Great Falls, MT, 32 km away, the last frost here is 16 days later than there and the growing season is 24 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 7 |
| 50% (median) | May 22 |
| 10% (safe for tender plants) | June 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 7 |
| 50% (median) | September 23 |
| 90% (late) | October 6 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Belt, MT
Belt, MT frost dates — last frost May 22, first frost Sep 23, zone 4b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 24 to May 8
Start indoors: Mar 13 to Mar 27Transplant outside: Jun 5 to Jun 19
Start indoors: Mar 13 to Mar 27Transplant outside: Jun 5 to Jun 19
Start indoors: Mar 27 to Apr 10Transplant outside: May 29 to Jun 12
Start indoors: Mar 27 to Apr 10Transplant outside: May 1 to May 15Sow outdoors: Apr 24 to May 29Plant for fall: Jul 29 to Aug 26
Start indoors: Mar 27 to Apr 10Transplant outside: Apr 24 to May 8Sow outdoors: Apr 24 to May 8Plant for fall: Jul 15 to Aug 5
Start indoors: Mar 27 to Apr 10Transplant outside: May 8 to May 22Plant for fall: Jun 17 to Jul 8
Start indoors: Mar 27 to Apr 10Transplant outside: May 1 to May 15Plant for fall: Jun 17 to Jul 8
Start indoors: Mar 27 to Apr 10Transplant outside: May 8 to May 22Plant for fall: Jun 17 to Jul 8
Start indoors: Apr 10 to Apr 24Transplant outside: Jun 12 to Jun 26Sow outdoors: Jun 12 to Jun 26
Start indoors: Apr 10 to Apr 24Transplant outside: May 29 to Jun 12
Sow outdoors: Apr 10 to May 1Plant for fall: Jul 1 to Jul 22
Sow outdoors: Apr 10 to May 1Plant for fall: Jul 29 to Aug 19
Sow outdoors: Apr 17 to May 29Plant for fall: Aug 12 to Sep 2
Start indoors: Apr 24 to May 1Transplant outside: Jun 5 to Jun 12Sow outdoors: May 29 to Jun 12Plant for fall: Jul 8 to Jul 22
Start indoors: Apr 24 to May 1Sow outdoors: May 29 to Jun 12Plant for fall: Jul 15 to Jul 29
Start indoors: Apr 24 to May 1Sow outdoors: May 29 to Jun 12
Start indoors: Apr 24 to May 1Transplant outside: Jun 5 to Jun 19
Sow outdoors: May 1 to May 29Plant for fall: Jul 1 to Jul 15
Sow outdoors: May 1 to May 29Plant for fall: Jul 15 to Jul 29
Sow outdoors: May 1 to May 22
Sow outdoors: May 8 to Jun 5Plant for fall: Jul 15 to Jul 29
Sow outdoors: May 8 to May 29Plant for fall: Jul 29 to Aug 19
Sow outdoors: May 29 to Jun 19Plant for fall: Jul 8 to Jul 22
Sow outdoors: May 29 to Jun 12
Transplant outside: Jun 5 to Jun 26
Plant for fall: Sep 9 to Oct 14
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Belt, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 27 – Mar 13 | Apr 24 – May 8 | — | — |
| Peppers | Mar 13 – Mar 27 | Jun 5 – Jun 19 | — | — |
| Eggplant | Mar 13 – Mar 27 | Jun 5 – Jun 19 | — | — |
| Tomatoes | Mar 27 – Apr 10 | May 29 – Jun 12 | — | — |
| Lettuce | Mar 27 – Apr 10 | May 1 – May 15 | Apr 24 – May 29 | Jul 29 – Aug 26 |
| Kale | Mar 27 – Apr 10 | Apr 24 – May 8 | Apr 24 – May 8 | Jul 15 – Aug 5 |
| Broccoli | Mar 27 – Apr 10 | May 8 – May 22 | — | Jun 17 – Jul 8 |
| Cabbage | Mar 27 – Apr 10 | May 1 – May 15 | — | Jun 17 – Jul 8 |
| Cauliflower | Mar 27 – Apr 10 | May 8 – May 22 | — | Jun 17 – Jul 8 |
| Okra | Apr 10 – Apr 24 | Jun 12 – Jun 26 | Jun 12 – Jun 26 | — |
| Basil | Apr 10 – Apr 24 | May 29 – Jun 12 | — | — |
| Peas | — | — | Apr 10 – May 1 | Jul 1 – Jul 22 |
| Spinach | — | — | Apr 10 – May 1 | Jul 29 – Aug 19 |
| Radishes | — | — | Apr 17 – May 29 | Aug 12 – Sep 2 |
| Cucumbers | Apr 24 – May 1 | Jun 5 – Jun 12 | May 29 – Jun 12 | Jul 8 – Jul 22 |
| Zucchini & Summer Squash | Apr 24 – May 1 | — | May 29 – Jun 12 | Jul 15 – Jul 29 |
| Winter Squash & Pumpkins | Apr 24 – May 1 | — | May 29 – Jun 12 | — |
| Melons & Watermelon | Apr 24 – May 1 | Jun 5 – Jun 19 | — | — |
| Carrots | — | — | May 1 – May 29 | Jul 1 – Jul 15 |
| Beets | — | — | May 1 – May 29 | Jul 15 – Jul 29 |
| Potatoes | — | — | May 1 – May 22 | — |
| Swiss Chard | — | — | May 8 – Jun 5 | Jul 15 – Jul 29 |
| Cilantro | — | — | May 8 – May 29 | Jul 29 – Aug 19 |
| Green Beans | — | — | May 29 – Jun 19 | Jul 8 – Jul 22 |
| Sweet Corn | — | — | May 29 – Jun 12 | — |
| Sweet Potatoes | — | Jun 5 – Jun 26 | — | — |
| Garlic | — | — | — | Sep 9 – Oct 14 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Raynesford 2 Nnw, MT weather station, 15 km away (elevation 4,216 ft (1,285 m)).
Frost dates near Belt
- Stockett May 6 · Oct 1
- Sand Coulee May 6 · Oct 1
- Raynesford May 22 · Sep 23
- Highwood May 7 · Oct 2
- Black Eagle May 6 · Oct 1
- Malmstrom Afb May 6 · Oct 1
- Great Falls May 6 · Oct 1
- Monarch Jun 6 · Sep 12
- Floweree May 23 · Sep 23
- Geyser May 22 · Sep 23
Frequently asked questions
When is the last frost in Belt, MT?
The median last spring frost in Belt, MT is May 22. There is still about a 10% chance of frost after June 9, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Belt, MT?
The median first fall frost is September 23, with about a 10% chance of frost before September 7.
How long is the growing season in Belt, MT?
About 124 days between the median last spring frost and first fall frost.
What planting zone is Belt, MT?
Belt, MT is in USDA hardiness zone 4b.