Havre, MT frost dates
Last spring frostMay 15median date
First fall frostSep 23median date
Growing season131 daysfrost-free
Hardiness zone3bZone 3b
How Havre compares
- In 8 years out of 10, the last spring frost in Havre falls between May 3 and May 27, a 24-day window. The first fall frost falls between September 11 and October 5.
- The median last frost is 4 days earlier than the Montana median of May 19.
- Its 131-day growing season is longer than 62% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is typical for zone 3b, where the median is May 17.
- The weather station records an average of 185 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 3 |
| 50% (median) | May 15 |
| 10% (safe for tender plants) | May 27 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 11 |
| 50% (median) | September 23 |
| 90% (late) | October 5 |
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 Havre, MT
Havre, MT frost dates — last frost May 15, first frost Sep 23, zone 3b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 20 to Mar 6Transplant outside: Apr 17 to May 1
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 20 to Apr 3Transplant outside: May 22 to Jun 5
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Sow outdoors: Apr 17 to May 22Plant for fall: Jul 29 to Aug 26
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 17 to May 1Sow outdoors: Apr 17 to May 1Plant for fall: Jul 15 to Aug 5
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jun 17 to Jul 8
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Plant for fall: Jun 17 to Jul 8
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jun 17 to Jul 8
Start indoors: Apr 3 to Apr 17Transplant outside: Jun 5 to Jun 19Sow outdoors: Jun 5 to Jun 19
Start indoors: Apr 3 to Apr 17Transplant outside: May 22 to Jun 5
Sow outdoors: Apr 3 to Apr 24Plant for fall: Jul 1 to Jul 22
Sow outdoors: Apr 3 to Apr 24Plant for fall: Jul 29 to Aug 19
Sow outdoors: Apr 10 to May 22Plant for fall: Aug 12 to Sep 2
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 5Sow outdoors: May 22 to Jun 5Plant for fall: Jul 8 to Jul 22
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5Plant for fall: Jul 15 to Jul 29
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 12
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 1 to Jul 15
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 15 to Jul 29
Sow outdoors: Apr 24 to May 15
Sow outdoors: May 1 to May 29Plant for fall: Jul 15 to Jul 29
Sow outdoors: May 1 to May 22Plant for fall: Jul 29 to Aug 19
Sow outdoors: May 22 to Jun 12Plant for fall: Jul 8 to Jul 22
Sow outdoors: May 22 to Jun 5
Transplant outside: May 29 to Jun 19
Plant for fall: Sep 9 to Oct 14
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Havre, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 20 – Mar 6 | Apr 17 – May 1 | — | — |
| Peppers | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Eggplant | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Tomatoes | Mar 20 – Apr 3 | May 22 – Jun 5 | — | — |
| Lettuce | Mar 20 – Apr 3 | Apr 24 – May 8 | Apr 17 – May 22 | Jul 29 – Aug 26 |
| Kale | Mar 20 – Apr 3 | Apr 17 – May 1 | Apr 17 – May 1 | Jul 15 – Aug 5 |
| Broccoli | Mar 20 – Apr 3 | May 1 – May 15 | — | Jun 17 – Jul 8 |
| Cabbage | Mar 20 – Apr 3 | Apr 24 – May 8 | — | Jun 17 – Jul 8 |
| Cauliflower | Mar 20 – Apr 3 | May 1 – May 15 | — | Jun 17 – Jul 8 |
| Okra | Apr 3 – Apr 17 | Jun 5 – Jun 19 | Jun 5 – Jun 19 | — |
| Basil | Apr 3 – Apr 17 | May 22 – Jun 5 | — | — |
| Peas | — | — | Apr 3 – Apr 24 | Jul 1 – Jul 22 |
| Spinach | — | — | Apr 3 – Apr 24 | Jul 29 – Aug 19 |
| Radishes | — | — | Apr 10 – May 22 | Aug 12 – Sep 2 |
| Cucumbers | Apr 17 – Apr 24 | May 29 – Jun 5 | May 22 – Jun 5 | Jul 8 – Jul 22 |
| Zucchini & Summer Squash | Apr 17 – Apr 24 | — | May 22 – Jun 5 | Jul 15 – Jul 29 |
| Winter Squash & Pumpkins | Apr 17 – Apr 24 | — | May 22 – Jun 5 | — |
| Melons & Watermelon | Apr 17 – Apr 24 | May 29 – Jun 12 | — | — |
| Carrots | — | — | Apr 24 – May 22 | Jul 1 – Jul 15 |
| Beets | — | — | Apr 24 – May 22 | Jul 15 – Jul 29 |
| Potatoes | — | — | Apr 24 – May 15 | — |
| Swiss Chard | — | — | May 1 – May 29 | Jul 15 – Jul 29 |
| Cilantro | — | — | May 1 – May 22 | Jul 29 – Aug 19 |
| Green Beans | — | — | May 22 – Jun 12 | Jul 8 – Jul 22 |
| Sweet Corn | — | — | May 22 – Jun 5 | — |
| Sweet Potatoes | — | May 29 – Jun 19 | — | — |
| Garlic | — | — | — | Sep 9 – Oct 14 |
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 Havre City Co Ap, MT weather station, 6 km away (elevation 2,585 ft (788 m)).
Frost dates near Havre
- Kremlin May 24 · Sep 15
- Box Elder May 15 · Sep 24
- Chinook May 14 · Sep 23
- Gildford May 24 · Sep 15
- Zurich May 14 · Sep 23
- Big Sandy May 17 · Sep 25
- Hingham May 24 · Sep 15
- Rudyard May 21 · Sep 19
- Harlem May 16 · Sep 21
- Lloyd May 23 · Sep 23
Frequently asked questions
When is the last frost in Havre, MT?
The median last spring frost in Havre, MT is May 15. There is still about a 10% chance of frost after May 27, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Havre, MT?
The median first fall frost is September 23, with about a 10% chance of frost before September 11.
How long is the growing season in Havre, MT?
About 131 days between the median last spring frost and first fall frost.
What planting zone is Havre, MT?
Havre, MT is in USDA hardiness zone 3b.