Warm Springs, MT frost dates
Last spring frostJun 1median date
First fall frostSep 14median date
Growing season105 daysfrost-free
Hardiness zone4bZone 4b
How Warm Springs compares
- In 8 years out of 10, the last spring frost in Warm Springs falls between May 14 and June 25, a 42-day window. The first fall frost falls between August 31 and October 1.
- The median last frost is 13 days later than the Montana median of May 19.
- Its 105-day growing season is longer than 17% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 24 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 201 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 14 |
| 50% (median) | June 1 |
| 10% (safe for tender plants) | June 25 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 31 |
| 50% (median) | September 14 |
| 90% (late) | October 1 |
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 Warm Springs, MT
Warm Springs, MT frost dates — last frost Jun 1, first frost Sep 14, zone 4b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 9 to Mar 23Transplant outside: May 4 to May 18
Start indoors: Mar 23 to Apr 6Transplant outside: Jun 15 to Jun 29
Start indoors: Mar 23 to Apr 6Transplant outside: Jun 15 to Jun 29
Start indoors: Apr 6 to Apr 20Transplant outside: Jun 8 to Jun 22
Start indoors: Apr 6 to Apr 20Transplant outside: May 11 to May 25Sow outdoors: May 4 to Jun 8Plant for fall: Jul 20 to Aug 17
Start indoors: Apr 6 to Apr 20Transplant outside: May 4 to May 18Sow outdoors: May 4 to May 18Plant for fall: Jul 6 to Jul 27
Start indoors: Apr 6 to Apr 20Transplant outside: May 18 to Jun 1
Start indoors: Apr 6 to Apr 20Transplant outside: May 11 to May 25
Start indoors: Apr 6 to Apr 20Transplant outside: May 18 to Jun 1
Start indoors: Apr 20 to May 4Transplant outside: Jun 22 to Jul 6Sow outdoors: Jun 22 to Jul 6
Start indoors: Apr 20 to May 4Transplant outside: Jun 8 to Jun 22
Sow outdoors: Apr 20 to May 11Plant for fall: Jun 22 to Jul 13
Sow outdoors: Apr 20 to May 11Plant for fall: Jul 20 to Aug 10
Sow outdoors: Apr 27 to Jun 8Plant for fall: Aug 3 to Aug 24
Start indoors: May 4 to May 11Transplant outside: Jun 15 to Jun 22Sow outdoors: Jun 8 to Jun 22
Start indoors: May 4 to May 11Sow outdoors: Jun 8 to Jun 22
Start indoors: May 4 to May 11Sow outdoors: Jun 8 to Jun 22
Start indoors: May 4 to May 11Transplant outside: Jun 15 to Jun 29
Sow outdoors: May 11 to Jun 8
Sow outdoors: May 11 to Jun 8Plant for fall: Jul 6 to Jul 20
Sow outdoors: May 11 to Jun 1
Sow outdoors: May 18 to Jun 15Plant for fall: Jul 6 to Jul 20
Sow outdoors: May 18 to Jun 8Plant for fall: Jul 20 to Aug 10
Sow outdoors: Jun 8 to Jun 29
Sow outdoors: Jun 8 to Jun 22
Transplant outside: Jun 15 to Jul 6
Plant for fall: Aug 31 to Oct 5
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Warm Springs, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 9 – Mar 23 | May 4 – May 18 | — | — |
| Peppers | Mar 23 – Apr 6 | Jun 15 – Jun 29 | — | — |
| Eggplant | Mar 23 – Apr 6 | Jun 15 – Jun 29 | — | — |
| Tomatoes | Apr 6 – Apr 20 | Jun 8 – Jun 22 | — | — |
| Lettuce | Apr 6 – Apr 20 | May 11 – May 25 | May 4 – Jun 8 | Jul 20 – Aug 17 |
| Kale | Apr 6 – Apr 20 | May 4 – May 18 | May 4 – May 18 | Jul 6 – Jul 27 |
| Broccoli | Apr 6 – Apr 20 | May 18 – Jun 1 | — | — |
| Cabbage | Apr 6 – Apr 20 | May 11 – May 25 | — | — |
| Cauliflower | Apr 6 – Apr 20 | May 18 – Jun 1 | — | — |
| Okra | Apr 20 – May 4 | Jun 22 – Jul 6 | Jun 22 – Jul 6 | — |
| Basil | Apr 20 – May 4 | Jun 8 – Jun 22 | — | — |
| Peas | — | — | Apr 20 – May 11 | Jun 22 – Jul 13 |
| Spinach | — | — | Apr 20 – May 11 | Jul 20 – Aug 10 |
| Radishes | — | — | Apr 27 – Jun 8 | Aug 3 – Aug 24 |
| Cucumbers | May 4 – May 11 | Jun 15 – Jun 22 | Jun 8 – Jun 22 | — |
| Zucchini & Summer Squash | May 4 – May 11 | — | Jun 8 – Jun 22 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 105 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 4 – May 11 | — | Jun 8 – Jun 22 | — |
| Melons & Watermelon | May 4 – May 11 | Jun 15 – Jun 29 | — | — |
| Carrots | — | — | May 11 – Jun 8 | — |
| Beets | — | — | May 11 – Jun 8 | Jul 6 – Jul 20 |
| Potatoes | — | — | May 11 – Jun 1 | — |
| Swiss Chard | — | — | May 18 – Jun 15 | Jul 6 – Jul 20 |
| Cilantro | — | — | May 18 – Jun 8 | Jul 20 – Aug 10 |
| Green Beans | — | — | Jun 8 – Jun 29 | — |
| Sweet Corn | — | — | Jun 8 – Jun 22 | — |
| Sweet Potatoes Warning: Your frost-free season is about 105 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 15 – Jul 6 | — | — |
| Garlic | — | — | — | Aug 31 – Oct 5 |
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 Anaconda, MT weather station, 13 km away (elevation 5,230 ft (1,594 m)).
Frost dates near Warm Springs
- Anaconda Jun 1 · Sep 14
- Ramsay Jun 13 · Sep 5
- Deer Lodge frost any month
- Butte Jun 13 · Sep 5
- Divide Jun 10 · Sep 7
- Philipsburg frost any month
- Garrison frost any month
- Elliston Jun 9 · Sep 8
- Gold Creek frost any month
- Basin Jun 7 · Sep 8
Frequently asked questions
When is the last frost in Warm Springs, MT?
The median last spring frost in Warm Springs, MT is June 1. There is still about a 10% chance of frost after June 25, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Warm Springs, MT?
The median first fall frost is September 14, with about a 10% chance of frost before August 31.
How long is the growing season in Warm Springs, MT?
About 105 days between the median last spring frost and first fall frost.
What planting zone is Warm Springs, MT?
Warm Springs, MT is in USDA hardiness zone 4b.