Frost dates for 59903 — Kalispell, MT
Last spring frostMay 31median date
First fall frostSep 10median date
Growing season102 daysfrost-free
Hardiness zone5bZone 5b
How Kalispell compares
- In 8 years out of 10, the last spring frost in Kalispell falls between May 13 and June 22, a 40-day window. The first fall frost falls between August 26 and September 25.
- The median last frost is 12 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 30 days later than the zone 5b median of May 1. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5b chart.
- The weather station records an average of 187 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 13 |
| 50% (median) | May 31 |
| 10% (safe for tender plants) | June 22 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 26 |
| 50% (median) | September 10 |
| 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 Kalispell, MT
Frost dates for 59903 — Kalispell, MT — last frost May 31, first frost Sep 10, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Mar 8 to Mar 22Transplant outside: May 3 to May 17
Start indoors: Mar 22 to Apr 5Transplant outside: Jun 14 to Jun 28
Start indoors: Mar 22 to Apr 5Transplant outside: Jun 14 to Jun 28
Start indoors: Apr 5 to Apr 19Transplant outside: Jun 7 to Jun 21
Start indoors: Apr 5 to Apr 19Transplant outside: May 10 to May 24Sow outdoors: May 3 to Jun 7Plant for fall: Jul 16 to Aug 13
Start indoors: Apr 5 to Apr 19Transplant outside: May 3 to May 17Sow outdoors: May 3 to May 17Plant for fall: Jul 2 to Jul 23
Start indoors: Apr 5 to Apr 19Transplant outside: May 17 to May 31
Start indoors: Apr 5 to Apr 19Transplant outside: May 10 to May 24
Start indoors: Apr 5 to Apr 19Transplant outside: May 17 to May 31
Start indoors: Apr 19 to May 3Transplant outside: Jun 21 to Jul 5Sow outdoors: Jun 21 to Jul 5
Start indoors: Apr 19 to May 3Transplant outside: Jun 7 to Jun 21
Sow outdoors: Apr 19 to May 10Plant for fall: Jun 18 to Jul 9
Sow outdoors: Apr 19 to May 10Plant for fall: Jul 16 to Aug 6
Sow outdoors: Apr 26 to Jun 7Plant for fall: Jul 30 to Aug 20
Start indoors: May 3 to May 10Transplant outside: Jun 14 to Jun 21Sow outdoors: Jun 7 to Jun 21
Start indoors: May 3 to May 10Sow outdoors: Jun 7 to Jun 21
Start indoors: May 3 to May 10Sow outdoors: Jun 7 to Jun 21
Start indoors: May 3 to May 10Transplant outside: Jun 14 to Jun 28
Sow outdoors: May 10 to Jun 7
Sow outdoors: May 10 to Jun 7Plant for fall: Jul 2 to Jul 16
Sow outdoors: May 10 to May 31
Sow outdoors: May 17 to Jun 14Plant for fall: Jul 2 to Jul 16
Sow outdoors: May 17 to Jun 7Plant for fall: Jul 16 to Aug 6
Sow outdoors: Jun 7 to Jun 28
Sow outdoors: Jun 7 to Jun 21
Transplant outside: Jun 14 to Jul 5
Plant for fall: Aug 27 to Oct 1
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Kalispell, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 8 – Mar 22 | May 3 – May 17 | — | — |
| Peppers | Mar 22 – Apr 5 | Jun 14 – Jun 28 | — | — |
| Eggplant | Mar 22 – Apr 5 | Jun 14 – Jun 28 | — | — |
| Tomatoes | Apr 5 – Apr 19 | Jun 7 – Jun 21 | — | — |
| Lettuce | Apr 5 – Apr 19 | May 10 – May 24 | May 3 – Jun 7 | Jul 16 – Aug 13 |
| Kale | Apr 5 – Apr 19 | May 3 – May 17 | May 3 – May 17 | Jul 2 – Jul 23 |
| Broccoli | Apr 5 – Apr 19 | May 17 – May 31 | — | — |
| Cabbage | Apr 5 – Apr 19 | May 10 – May 24 | — | — |
| Cauliflower | Apr 5 – Apr 19 | May 17 – May 31 | — | — |
| Okra | Apr 19 – May 3 | Jun 21 – Jul 5 | Jun 21 – Jul 5 | — |
| Basil | Apr 19 – May 3 | Jun 7 – Jun 21 | — | — |
| Peas | — | — | Apr 19 – May 10 | Jun 18 – Jul 9 |
| Spinach | — | — | Apr 19 – May 10 | Jul 16 – Aug 6 |
| Radishes | — | — | Apr 26 – Jun 7 | Jul 30 – Aug 20 |
| Cucumbers | May 3 – May 10 | Jun 14 – Jun 21 | Jun 7 – Jun 21 | — |
| Zucchini & Summer Squash | May 3 – May 10 | — | Jun 7 – Jun 21 | — |
| 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 3 – May 10 | — | Jun 7 – Jun 21 | — |
| Melons & Watermelon | May 3 – May 10 | Jun 14 – Jun 28 | — | — |
| Carrots | — | — | May 10 – Jun 7 | — |
| Beets | — | — | May 10 – Jun 7 | Jul 2 – Jul 16 |
| Potatoes | — | — | May 10 – May 31 | — |
| Swiss Chard | — | — | May 17 – Jun 14 | Jul 2 – Jul 16 |
| Cilantro | — | — | May 17 – Jun 7 | Jul 16 – Aug 6 |
| Green Beans | — | — | Jun 7 – Jun 28 | — |
| Sweet Corn | — | — | Jun 7 – Jun 21 | — |
| 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 14 – Jul 5 | — | — |
| Garlic | — | — | — | Aug 27 – Oct 1 |
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 Kalispell Glacier Ap, MT weather station, 15 km away (elevation 2,956 ft (901 m)).
ZIP codes in Kalispell: 59901 59903 59904
Frost dates near Kalispell
- Kila May 12 · Sep 25
- Whitefish May 16 · Sep 25
- Somers May 12 · Sep 25
- Columbia Falls May 31 · Sep 10
- Lakeside May 12 · Sep 25
- Marion frost any month
- Proctor May 1 · Oct 15
- Bigfork May 12 · Sep 25
Frequently asked questions
When is the last frost in Kalispell, MT?
The median last spring frost in Kalispell, MT is May 31. There is still about a 10% chance of frost after June 22, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Kalispell, MT?
The median first fall frost is September 10, with about a 10% chance of frost before August 26.
How long is the growing season in Kalispell, MT?
About 102 days between the median last spring frost and first fall frost.
What planting zone is Kalispell, MT?
Kalispell, MT is in USDA hardiness zone 5b.