Fallon, MT frost dates
Last spring frostMay 20median date
First fall frostSep 22median date
Growing season125 daysfrost-free
Hardiness zone4aZone 4a
How Fallon compares
- In 8 years out of 10, the last spring frost in Fallon falls between May 6 and June 2, a 27-day window. The first fall frost falls between September 7 and October 6.
- The median last frost is 1 day later than the Montana median of May 19.
- Its 125-day growing season is longer than 47% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 8 days later than the zone 4a median of May 12. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4a chart.
- The weather station records an average of 191 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 6 |
| 50% (median) | May 20 |
| 10% (safe for tender plants) | June 2 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 7 |
| 50% (median) | September 22 |
| 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 Fallon, MT
Fallon, MT frost dates — last frost May 20, first frost Sep 22, zone 4a. whenisthelastfrost.com
Crop
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Start indoors: Feb 25 to Mar 11Transplant outside: Apr 22 to May 6
Start indoors: Mar 11 to Mar 25Transplant outside: Jun 3 to Jun 17
Start indoors: Mar 11 to Mar 25Transplant outside: Jun 3 to Jun 17
Start indoors: Mar 25 to Apr 8Transplant outside: May 27 to Jun 10
Start indoors: Mar 25 to Apr 8Transplant outside: Apr 29 to May 13Sow outdoors: Apr 22 to May 27Plant for fall: Jul 28 to Aug 25
Start indoors: Mar 25 to Apr 8Transplant outside: Apr 22 to May 6Sow outdoors: Apr 22 to May 6Plant for fall: Jul 14 to Aug 4
Start indoors: Mar 25 to Apr 8Transplant outside: May 6 to May 20Plant for fall: Jun 16 to Jul 7
Start indoors: Mar 25 to Apr 8Transplant outside: Apr 29 to May 13Plant for fall: Jun 16 to Jul 7
Start indoors: Mar 25 to Apr 8Transplant outside: May 6 to May 20Plant for fall: Jun 16 to Jul 7
Start indoors: Apr 8 to Apr 22Transplant outside: Jun 10 to Jun 24Sow outdoors: Jun 10 to Jun 24
Start indoors: Apr 8 to Apr 22Transplant outside: May 27 to Jun 10
Sow outdoors: Apr 8 to Apr 29Plant for fall: Jun 30 to Jul 21
Sow outdoors: Apr 8 to Apr 29Plant for fall: Jul 28 to Aug 18
Sow outdoors: Apr 15 to May 27Plant for fall: Aug 11 to Sep 1
Start indoors: Apr 22 to Apr 29Transplant outside: Jun 3 to Jun 10Sow outdoors: May 27 to Jun 10Plant for fall: Jul 7 to Jul 21
Start indoors: Apr 22 to Apr 29Sow outdoors: May 27 to Jun 10Plant for fall: Jul 14 to Jul 28
Start indoors: Apr 22 to Apr 29Sow outdoors: May 27 to Jun 10
Start indoors: Apr 22 to Apr 29Transplant outside: Jun 3 to Jun 17
Sow outdoors: Apr 29 to May 27Plant for fall: Jun 30 to Jul 14
Sow outdoors: Apr 29 to May 27Plant for fall: Jul 14 to Jul 28
Sow outdoors: Apr 29 to May 20
Sow outdoors: May 6 to Jun 3Plant for fall: Jul 14 to Jul 28
Sow outdoors: May 6 to May 27Plant for fall: Jul 28 to Aug 18
Sow outdoors: May 27 to Jun 17Plant for fall: Jul 7 to Jul 21
Sow outdoors: May 27 to Jun 10
Transplant outside: Jun 3 to Jun 24
Plant for fall: Sep 8 to Oct 13
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Fallon, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 25 – Mar 11 | Apr 22 – May 6 | — | — |
| Peppers | Mar 11 – Mar 25 | Jun 3 – Jun 17 | — | — |
| Eggplant | Mar 11 – Mar 25 | Jun 3 – Jun 17 | — | — |
| Tomatoes | Mar 25 – Apr 8 | May 27 – Jun 10 | — | — |
| Lettuce | Mar 25 – Apr 8 | Apr 29 – May 13 | Apr 22 – May 27 | Jul 28 – Aug 25 |
| Kale | Mar 25 – Apr 8 | Apr 22 – May 6 | Apr 22 – May 6 | Jul 14 – Aug 4 |
| Broccoli | Mar 25 – Apr 8 | May 6 – May 20 | — | Jun 16 – Jul 7 |
| Cabbage | Mar 25 – Apr 8 | Apr 29 – May 13 | — | Jun 16 – Jul 7 |
| Cauliflower | Mar 25 – Apr 8 | May 6 – May 20 | — | Jun 16 – Jul 7 |
| Okra | Apr 8 – Apr 22 | Jun 10 – Jun 24 | Jun 10 – Jun 24 | — |
| Basil | Apr 8 – Apr 22 | May 27 – Jun 10 | — | — |
| Peas | — | — | Apr 8 – Apr 29 | Jun 30 – Jul 21 |
| Spinach | — | — | Apr 8 – Apr 29 | Jul 28 – Aug 18 |
| Radishes | — | — | Apr 15 – May 27 | Aug 11 – Sep 1 |
| Cucumbers | Apr 22 – Apr 29 | Jun 3 – Jun 10 | May 27 – Jun 10 | Jul 7 – Jul 21 |
| Zucchini & Summer Squash | Apr 22 – Apr 29 | — | May 27 – Jun 10 | Jul 14 – Jul 28 |
| Winter Squash & Pumpkins | Apr 22 – Apr 29 | — | May 27 – Jun 10 | — |
| Melons & Watermelon | Apr 22 – Apr 29 | Jun 3 – Jun 17 | — | — |
| Carrots | — | — | Apr 29 – May 27 | Jun 30 – Jul 14 |
| Beets | — | — | Apr 29 – May 27 | Jul 14 – Jul 28 |
| Potatoes | — | — | Apr 29 – May 20 | — |
| Swiss Chard | — | — | May 6 – Jun 3 | Jul 14 – Jul 28 |
| Cilantro | — | — | May 6 – May 27 | Jul 28 – Aug 18 |
| Green Beans | — | — | May 27 – Jun 17 | Jul 7 – Jul 21 |
| Sweet Corn | — | — | May 27 – Jun 10 | — |
| Sweet Potatoes | — | Jun 3 – Jun 24 | — | — |
| Garlic | — | — | — | Sep 8 – Oct 13 |
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 Mildred 5 N, MT weather station, 12 km away (elevation 2,484 ft (757 m)).
Frost dates near Fallon
- Mildred May 20 · Sep 22
- Terry May 12 · Sep 28
- Ismay May 22 · Sep 15
- Glendive May 3 · Oct 4
- Lindsay May 26 · Sep 17
- Kinsey May 8 · Sep 30
- Plevna May 21 · Sep 20
- Miles City May 8 · Sep 30
- Bloomfield May 3 · Oct 4
- Brockway May 20 · Sep 19
Frequently asked questions
When is the last frost in Fallon, MT?
The median last spring frost in Fallon, MT is May 20. There is still about a 10% chance of frost after June 2, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Fallon, MT?
The median first fall frost is September 22, with about a 10% chance of frost before September 7.
How long is the growing season in Fallon, MT?
About 125 days between the median last spring frost and first fall frost.
What planting zone is Fallon, MT?
Fallon, MT is in USDA hardiness zone 4a.