Fort Peck, MT frost dates
Last spring frostMay 8median date
First fall frostOct 1median date
Growing season146 daysfrost-free
Hardiness zone4aZone 4a
How Fort Peck compares
- In 8 years out of 10, the last spring frost in Fort Peck falls between April 25 and May 20, a 25-day window. The first fall frost falls between September 18 and October 16.
- The median last frost is 11 days earlier than the Montana median of May 19.
- Its 146-day growing season is longer than 92% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 4 days earlier 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 164 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 25 |
| 50% (median) | May 8 |
| 10% (safe for tender plants) | May 20 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 18 |
| 50% (median) | October 1 |
| 90% (late) | October 16 |
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 Fort Peck, MT
Fort Peck, MT frost dates — last frost May 8, first frost Oct 1, zone 4a. whenisthelastfrost.com
Crop
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Start indoors: Feb 13 to Feb 27Transplant outside: Apr 10 to Apr 24
Start indoors: Feb 27 to Mar 13Transplant outside: May 22 to Jun 5
Start indoors: Feb 27 to Mar 13Transplant outside: May 22 to Jun 5
Start indoors: Mar 13 to Mar 27Transplant outside: May 15 to May 29
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 17 to May 1Sow outdoors: Apr 10 to May 15Plant for fall: Aug 6 to Sep 3
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 10 to Apr 24Sow outdoors: Apr 10 to Apr 24Plant for fall: Jul 23 to Aug 13
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 24 to May 8Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 17 to May 1Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 24 to May 8Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 27 to Apr 10Transplant outside: May 29 to Jun 12Sow outdoors: May 29 to Jun 12
Start indoors: Mar 27 to Apr 10Transplant outside: May 15 to May 29
Sow outdoors: Mar 27 to Apr 17Plant for fall: Jul 9 to Jul 30
Sow outdoors: Mar 27 to Apr 17Plant for fall: Aug 6 to Aug 27
Sow outdoors: Apr 3 to May 15Plant for fall: Aug 20 to Sep 10
Start indoors: Apr 10 to Apr 17Transplant outside: May 22 to May 29Sow outdoors: May 15 to May 29Plant for fall: Jul 16 to Jul 30
Start indoors: Apr 10 to Apr 17Sow outdoors: May 15 to May 29Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 10 to Apr 17Sow outdoors: May 15 to May 29
Start indoors: Apr 10 to Apr 17Transplant outside: May 22 to Jun 5
Sow outdoors: Apr 17 to May 15Plant for fall: Jul 9 to Jul 23
Sow outdoors: Apr 17 to May 15Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 17 to May 8
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 24 to May 15Plant for fall: Aug 6 to Aug 27
Sow outdoors: May 15 to Jun 5Plant for fall: Jul 16 to Jul 30
Sow outdoors: May 15 to May 29
Transplant outside: May 22 to Jun 12
Plant for fall: Sep 17 to Oct 22
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Fort Peck, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 13 – Feb 27 | Apr 10 – Apr 24 | — | — |
| Peppers | Feb 27 – Mar 13 | May 22 – Jun 5 | — | — |
| Eggplant | Feb 27 – Mar 13 | May 22 – Jun 5 | — | — |
| Tomatoes | Mar 13 – Mar 27 | May 15 – May 29 | — | — |
| Lettuce | Mar 13 – Mar 27 | Apr 17 – May 1 | Apr 10 – May 15 | Aug 6 – Sep 3 |
| Kale | Mar 13 – Mar 27 | Apr 10 – Apr 24 | Apr 10 – Apr 24 | Jul 23 – Aug 13 |
| Broccoli | Mar 13 – Mar 27 | Apr 24 – May 8 | — | Jun 25 – Jul 16 |
| Cabbage | Mar 13 – Mar 27 | Apr 17 – May 1 | — | Jun 25 – Jul 16 |
| Cauliflower | Mar 13 – Mar 27 | Apr 24 – May 8 | — | Jun 25 – Jul 16 |
| Okra | Mar 27 – Apr 10 | May 29 – Jun 12 | May 29 – Jun 12 | — |
| Basil | Mar 27 – Apr 10 | May 15 – May 29 | — | — |
| Peas | — | — | Mar 27 – Apr 17 | Jul 9 – Jul 30 |
| Spinach | — | — | Mar 27 – Apr 17 | Aug 6 – Aug 27 |
| Radishes | — | — | Apr 3 – May 15 | Aug 20 – Sep 10 |
| Cucumbers | Apr 10 – Apr 17 | May 22 – May 29 | May 15 – May 29 | Jul 16 – Jul 30 |
| Zucchini & Summer Squash | Apr 10 – Apr 17 | — | May 15 – May 29 | Jul 23 – Aug 6 |
| Winter Squash & Pumpkins | Apr 10 – Apr 17 | — | May 15 – May 29 | — |
| Melons & Watermelon | Apr 10 – Apr 17 | May 22 – Jun 5 | — | — |
| Carrots | — | — | Apr 17 – May 15 | Jul 9 – Jul 23 |
| Beets | — | — | Apr 17 – May 15 | Jul 23 – Aug 6 |
| Potatoes | — | — | Apr 17 – May 8 | — |
| Swiss Chard | — | — | Apr 24 – May 22 | Jul 23 – Aug 6 |
| Cilantro | — | — | Apr 24 – May 15 | Aug 6 – Aug 27 |
| Green Beans | — | — | May 15 – Jun 5 | Jul 16 – Jul 30 |
| Sweet Corn | — | — | May 15 – May 29 | — |
| Sweet Potatoes | — | May 22 – Jun 12 | — | — |
| Garlic | — | — | — | Sep 17 – Oct 22 |
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 Ft Peck Pwr Plt, MT weather station, 3 km away (elevation 2,070 ft (631 m)).
Frost dates near Fort Peck
- Nashua May 12 · Sep 24
- Glasgow May 6 · Sep 30
- Frazer May 12 · Sep 24
- Saint Marie May 13 · Sep 27
- Vandalia May 15 · Sep 26
- Hinsdale May 15 · Sep 26
- Wolf Point May 8 · Sep 28
- Larslan Jun 5 · Sep 2
- Vida May 16 · Sep 22
- Richland Jun 5 · Sep 2
Frequently asked questions
When is the last frost in Fort Peck, MT?
The median last spring frost in Fort Peck, MT is May 8. There is still about a 10% chance of frost after May 20, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Fort Peck, MT?
The median first fall frost is October 1, with about a 10% chance of frost before September 18.
How long is the growing season in Fort Peck, MT?
About 146 days between the median last spring frost and first fall frost.
What planting zone is Fort Peck, MT?
Fort Peck, MT is in USDA hardiness zone 4a.