Denton, MT frost dates
Last spring frostJun 1median date
First fall frostSep 11median date
Growing season102 daysfrost-free
Hardiness zone4bZone 4b
How Denton compares
- In 8 years out of 10, the last spring frost in Denton falls between May 15 and June 26, a 42-day window. The first fall frost falls between August 29 and September 25.
- The median last frost is 13 days later than the Montana median of May 19.
- Its 102-day growing season is longer than 13% 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 204 nights a year at or below 32°F.
- Compared with Great Falls, MT, 108 km away, the last frost here is 26 days later than there and the growing season is 46 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 15 |
| 50% (median) | June 1 |
| 10% (safe for tender plants) | June 26 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 29 |
| 50% (median) | September 11 |
| 90% (late) | September 25 |
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 Denton, MT
Denton, MT frost dates — last frost Jun 1, first frost Sep 11, 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 17 to Aug 14
Start indoors: Apr 6 to Apr 20Transplant outside: May 4 to May 18Sow outdoors: May 4 to May 18Plant for fall: Jul 3 to Jul 24
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 19 to Jul 10
Sow outdoors: Apr 20 to May 11Plant for fall: Jul 17 to Aug 7
Sow outdoors: Apr 27 to Jun 8Plant for fall: Jul 31 to Aug 21
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 3 to Jul 17
Sow outdoors: May 11 to Jun 1
Sow outdoors: May 18 to Jun 15Plant for fall: Jul 3 to Jul 17
Sow outdoors: May 18 to Jun 8Plant for fall: Jul 17 to Aug 7
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 28 to Oct 2
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Denton, 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 17 – Aug 14 |
| Kale | Apr 6 – Apr 20 | May 4 – May 18 | May 4 – May 18 | Jul 3 – Jul 24 |
| 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 19 – Jul 10 |
| Spinach | — | — | Apr 20 – May 11 | Jul 17 – Aug 7 |
| Radishes | — | — | Apr 27 – Jun 8 | Jul 31 – Aug 21 |
| 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 102 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 3 – Jul 17 |
| Potatoes | — | — | May 11 – Jun 1 | — |
| Swiss Chard | — | — | May 18 – Jun 15 | Jul 3 – Jul 17 |
| Cilantro | — | — | May 18 – Jun 8 | Jul 17 – Aug 7 |
| Green Beans | — | — | Jun 8 – Jun 29 | — |
| Sweet Corn | — | — | Jun 8 – Jun 22 | — |
| Sweet Potatoes Warning: Your frost-free season is about 102 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 15 – Jul 6 | — | — |
| Garlic | — | — | — | Aug 28 – Oct 2 |
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 Denton, MT weather station, 4 km away (elevation 3,609 ft (1,100 m)).
Frost dates near Denton
- Coffee Creek Jun 1 · Sep 11
- Moccasin May 28 · Sep 20
- Stanford May 25 · Sep 21
- Hobson May 28 · Sep 20
- Hilger May 14 · Sep 28
- Moore May 23 · Sep 21
- Geraldine May 14 · Sep 26
- Lewistown May 14 · Sep 28
- Geyser May 22 · Sep 23
- Buffalo Jun 1 · Sep 15
Frequently asked questions
When is the last frost in Denton, MT?
The median last spring frost in Denton, MT is June 1. There is still about a 10% chance of frost after June 26, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Denton, MT?
The median first fall frost is September 11, with about a 10% chance of frost before August 29.
How long is the growing season in Denton, MT?
About 102 days between the median last spring frost and first fall frost.
What planting zone is Denton, MT?
Denton, MT is in USDA hardiness zone 4b.