Choteau, MT frost dates
Last spring frostMay 28median date
First fall frostSep 12median date
Growing season107 daysfrost-free
Hardiness zone4bZone 4b
How Choteau compares
- In 8 years out of 10, the last spring frost in Choteau falls between May 15 and June 20, a 36-day window. The first fall frost falls between August 30 and September 27.
- The median last frost is 9 days later than the Montana median of May 19.
- Its 107-day growing season is longer than 19% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 20 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 177 nights a year at or below 32°F.
- Compared with Great Falls, MT, 77 km away, the last frost here is 22 days later than there and the growing season is 41 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 15 |
| 50% (median) | May 28 |
| 10% (safe for tender plants) | June 20 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 30 |
| 50% (median) | September 12 |
| 90% (late) | September 27 |
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 Choteau, MT
Choteau, MT frost dates — last frost May 28, first frost Sep 12, zone 4b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 30 to May 14
Start indoors: Mar 19 to Apr 2Transplant outside: Jun 11 to Jun 25
Start indoors: Mar 19 to Apr 2Transplant outside: Jun 11 to Jun 25
Start indoors: Apr 2 to Apr 16Transplant outside: Jun 4 to Jun 18
Start indoors: Apr 2 to Apr 16Transplant outside: May 7 to May 21Sow outdoors: Apr 30 to Jun 4Plant for fall: Jul 18 to Aug 15
Start indoors: Apr 2 to Apr 16Transplant outside: Apr 30 to May 14Sow outdoors: Apr 30 to May 14Plant for fall: Jul 4 to Jul 25
Start indoors: Apr 2 to Apr 16Transplant outside: May 14 to May 28
Start indoors: Apr 2 to Apr 16Transplant outside: May 7 to May 21
Start indoors: Apr 2 to Apr 16Transplant outside: May 14 to May 28
Start indoors: Apr 16 to Apr 30Transplant outside: Jun 18 to Jul 2Sow outdoors: Jun 18 to Jul 2
Start indoors: Apr 16 to Apr 30Transplant outside: Jun 4 to Jun 18
Sow outdoors: Apr 16 to May 7Plant for fall: Jun 20 to Jul 11
Sow outdoors: Apr 16 to May 7Plant for fall: Jul 18 to Aug 8
Sow outdoors: Apr 23 to Jun 4Plant for fall: Aug 1 to Aug 22
Start indoors: Apr 30 to May 7Transplant outside: Jun 11 to Jun 18Sow outdoors: Jun 4 to Jun 18
Start indoors: Apr 30 to May 7Sow outdoors: Jun 4 to Jun 18Plant for fall: Jul 4 to Jul 18
Start indoors: Apr 30 to May 7Sow outdoors: Jun 4 to Jun 18
Start indoors: Apr 30 to May 7Transplant outside: Jun 11 to Jun 25
Sow outdoors: May 7 to Jun 4Plant for fall: Jun 20 to Jul 4
Sow outdoors: May 7 to Jun 4Plant for fall: Jul 4 to Jul 18
Sow outdoors: May 7 to May 28
Sow outdoors: May 14 to Jun 11Plant for fall: Jul 4 to Jul 18
Sow outdoors: May 14 to Jun 4Plant for fall: Jul 18 to Aug 8
Sow outdoors: Jun 4 to Jun 25
Sow outdoors: Jun 4 to Jun 18
Transplant outside: Jun 11 to Jul 2
Plant for fall: Aug 29 to Oct 3
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Choteau, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 5 – Mar 19 | Apr 30 – May 14 | — | — |
| Peppers | Mar 19 – Apr 2 | Jun 11 – Jun 25 | — | — |
| Eggplant | Mar 19 – Apr 2 | Jun 11 – Jun 25 | — | — |
| Tomatoes | Apr 2 – Apr 16 | Jun 4 – Jun 18 | — | — |
| Lettuce | Apr 2 – Apr 16 | May 7 – May 21 | Apr 30 – Jun 4 | Jul 18 – Aug 15 |
| Kale | Apr 2 – Apr 16 | Apr 30 – May 14 | Apr 30 – May 14 | Jul 4 – Jul 25 |
| Broccoli | Apr 2 – Apr 16 | May 14 – May 28 | — | — |
| Cabbage | Apr 2 – Apr 16 | May 7 – May 21 | — | — |
| Cauliflower | Apr 2 – Apr 16 | May 14 – May 28 | — | — |
| Okra | Apr 16 – Apr 30 | Jun 18 – Jul 2 | Jun 18 – Jul 2 | — |
| Basil | Apr 16 – Apr 30 | Jun 4 – Jun 18 | — | — |
| Peas | — | — | Apr 16 – May 7 | Jun 20 – Jul 11 |
| Spinach | — | — | Apr 16 – May 7 | Jul 18 – Aug 8 |
| Radishes | — | — | Apr 23 – Jun 4 | Aug 1 – Aug 22 |
| Cucumbers | Apr 30 – May 7 | Jun 11 – Jun 18 | Jun 4 – Jun 18 | — |
| Zucchini & Summer Squash | Apr 30 – May 7 | — | Jun 4 – Jun 18 | Jul 4 – Jul 18 |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 107 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | Apr 30 – May 7 | — | Jun 4 – Jun 18 | — |
| Melons & Watermelon | Apr 30 – May 7 | Jun 11 – Jun 25 | — | — |
| Carrots | — | — | May 7 – Jun 4 | Jun 20 – Jul 4 |
| Beets | — | — | May 7 – Jun 4 | Jul 4 – Jul 18 |
| Potatoes | — | — | May 7 – May 28 | — |
| Swiss Chard | — | — | May 14 – Jun 11 | Jul 4 – Jul 18 |
| Cilantro | — | — | May 14 – Jun 4 | Jul 18 – Aug 8 |
| Green Beans | — | — | Jun 4 – Jun 25 | — |
| Sweet Corn | — | — | Jun 4 – Jun 18 | — |
| Sweet Potatoes Warning: Your frost-free season is about 107 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 11 – Jul 2 | — | — |
| Garlic | — | — | — | Aug 29 – Oct 3 |
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 Choteau, MT weather station, 2 km away (elevation 3,845 ft (1,172 m)).
Frost dates near Choteau
- Bynum May 16 · Sep 27
- Fairfield May 13 · Sep 27
- Pendroy Jun 9 · Sep 3
- Dutton May 20 · Sep 22
- Brady May 20 · Sep 19
- Power May 13 · Sep 27
- Conrad May 20 · Sep 19
- Simms Jun 2 · Sep 10
- Augusta May 19 · Sep 21
- Dupuyer Jun 9 · Sep 3
Frequently asked questions
When is the last frost in Choteau, MT?
The median last spring frost in Choteau, MT is May 28. There is still about a 10% chance of frost after June 20, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Choteau, MT?
The median first fall frost is September 12, with about a 10% chance of frost before August 30.
How long is the growing season in Choteau, MT?
About 107 days between the median last spring frost and first fall frost.
What planting zone is Choteau, MT?
Choteau, MT is in USDA hardiness zone 4b.