Montana Frost Dates
Across Montana's 128 cities and towns, the average last spring frost runs from May 3 in Glasgow to June 16 in Ennis. Average last frost elsewhere: Billings May 5, Missoula May 10 and Bozeman May 26. In 6 towns, frost is possible in any month.
Frost dates for every city and town in Montana
Dates are for 32°F at the NOAA station nearest the ZIP code at each Montana town's center. "Safer date" is when only 1 year in 10 still gets a frost, a good target for tomatoes and peppers.
| City | Average last frost | Safer date | Average first frost | Frost-free days |
|---|---|---|---|---|
| Alberton | May 18 | Jun 6 | Sep 25 | 130 |
| Anaconda-Deer Lodge County | Jun 1 | Jun 25 | Sep 14 | 105 |
| Bainville | May 21 | Jun 3 | Sep 20 | 122 |
| Baker | May 16 | May 29 | Sep 26 | 133 |
| Bearcreek | Jun 3 | Jun 18 | Sep 19 | 108 |
| Belgrade | May 26 | Jun 12 | Sep 15 | 112 |
| Belt | May 22 | Jun 9 | Sep 23 | 124 |
| Big Sandy | May 17 | Jun 4 | Sep 25 | 131 |
| Big Timber | May 14 | May 27 | Sep 26 | 135 |
| Billings | May 5 | May 21 | Oct 3 | 151 |
| Boulder | Jun 7 | Jun 25 | Sep 8 | 93 |
| Bozeman | May 26 | Jun 14 | Sep 22 | 119 |
| Bridger | May 14 | May 30 | Sep 24 | 133 |
| Broadus | May 16 | May 29 | Sep 28 | 135 |
| Broadview | May 22 | Jun 4 | Sep 15 | 116 |
| Browning | Jun 12 | Jul 3 | Sep 5 | 85 |
| Butte-Silver Bow | Jun 13 | Jul 1 | Sep 5 | 84 |
| Cascade | Jun 2 | Jun 21 | Sep 10 | 100 |
| Chester | May 24 | Jun 9 | Sep 17 | 116 |
| Chinook | May 14 | May 27 | Sep 23 | 132 |
| Choteau | May 16 | May 28 | Sep 27 | 134 |
| Circle | May 17 | May 31 | Sep 22 | 128 |
| Clyde Park | Jun 4 | Jun 23 | Sep 6 | 94 |
| Colstrip | May 15 | May 28 | Sep 30 | 138 |
| Columbia Falls | May 9 | May 30 | Oct 1 | 145 |
| Columbus | May 27 | Jun 12 | Sep 14 | 110 |
| Conrad | May 20 | Jun 3 | Sep 19 | 122 |
| Culbertson | May 21 | Jun 3 | Sep 20 | 122 |
| Cut Bank | May 24 | Jun 5 | Sep 15 | 114 |
| Darby | May 21 | Jun 6 | Sep 22 | 124 |
| Deer Lodge | Frost possible any month | |||
| Denton | Jun 1 | Jun 26 | Sep 11 | 102 |
| Dillon | Frost possible any month | |||
| Dodson | May 24 | Jun 11 | Sep 22 | 121 |
| Drummond | Frost possible any month | |||
| Dutton | May 20 | Jun 4 | Sep 22 | 125 |
| East Helena | May 9 | May 25 | Sep 30 | 144 |
| Ekalaka | May 20 | Jun 1 | Sep 23 | 126 |
| Ennis | Jun 16 | Jul 6 | Sep 4 | 80 |
| Eureka | May 11 | May 25 | Sep 27 | 139 |
| Fairfield | May 13 | Jun 1 | Sep 27 | 137 |
| Fairview | May 11 | May 25 | Sep 27 | 139 |
| Flaxville | May 28 | Jun 13 | Sep 7 | 102 |
| Forsyth | May 9 | May 21 | Sep 29 | 143 |
| Fort Benton | May 15 | May 30 | Sep 22 | 130 |
| Fort Peck | May 8 | May 20 | Oct 1 | 146 |
| Froid | May 16 | May 30 | Sep 18 | 125 |
| Fromberg | May 14 | May 30 | Sep 24 | 133 |
| Geraldine | May 14 | May 28 | Sep 26 | 135 |
| Glasgow | May 3 | May 15 | Oct 1 | 151 |
| Glendive | May 3 | May 16 | Oct 4 | 154 |
| Grass Range | May 20 | Jun 6 | Sep 24 | 127 |
| Great Falls | May 6 | May 19 | Oct 1 | 148 |
| Hamilton | May 21 | Jun 6 | Sep 22 | 124 |
| Hardin | May 13 | May 26 | Sep 29 | 139 |
| Harlem | May 16 | May 28 | Sep 22 | 129 |
| Harlowton | May 23 | Jun 6 | Sep 16 | 116 |
| Havre | May 15 | May 27 | Sep 23 | 131 |
| Helena | May 9 | May 25 | Sep 30 | 144 |
| Hingham | May 24 | Jun 7 | Sep 15 | 114 |
| Hobson | May 28 | Jun 19 | Sep 20 | 115 |
| Hot Springs | May 15 | Jun 1 | Sep 28 | 136 |
| Hysham | May 10 | May 22 | Sep 29 | 142 |
| Ismay | May 21 | Jun 4 | Sep 20 | 122 |
| Joliet | May 29 | Jun 17 | Sep 15 | 109 |
| Jordan | May 21 | Jun 2 | Sep 18 | 120 |
| Judith Gap | Jun 1 | Jun 16 | Sep 15 | 106 |
| Kalispell | May 31 | Jun 22 | Sep 10 | 102 |
| Kevin | May 23 | Jun 6 | Sep 16 | 116 |
| Laurel | May 5 | May 21 | Oct 3 | 151 |
| Lavina | May 17 | May 30 | Sep 23 | 129 |
| Lewistown | May 14 | May 27 | Sep 28 | 137 |
| Libby | May 10 | May 26 | Sep 26 | 139 |
| Lima | Jun 11 | Jun 30 | Sep 10 | 91 |
| Livingston | May 19 | Jun 11 | Sep 25 | 129 |
| Lodge Grass | May 21 | Jun 2 | Sep 17 | 119 |
| Malta | May 25 | Jun 8 | Sep 14 | 112 |
| Manhattan | May 26 | Jun 12 | Sep 15 | 112 |
| Medicine Lake | May 16 | May 30 | Sep 18 | 125 |
| Melstone | May 10 | May 23 | Sep 29 | 142 |
| Miles City | May 8 | May 21 | Sep 30 | 145 |
| Missoula | May 10 | May 28 | Oct 1 | 144 |
| Moore | May 31 | Jun 18 | Sep 14 | 106 |
| Nashua | May 12 | May 26 | Sep 24 | 135 |
| Neihart | Jun 6 | Jun 28 | Sep 12 | 98 |
| Opheim | Jun 1 | Jun 18 | Sep 7 | 98 |
| Outlook | May 28 | Jun 13 | Sep 7 | 102 |
| Philipsburg | Frost possible any month | |||
| Pinesdale | May 23 | Jun 10 | Sep 21 | 121 |
| Plains | Frost possible any month | |||
| Plentywood | May 25 | Jun 8 | Sep 14 | 112 |
| Plevna | May 21 | Jun 4 | Sep 20 | 122 |
| Polson | May 10 | May 26 | Oct 5 | 148 |
| Poplar | May 24 | Jun 6 | Sep 14 | 113 |
| Red Lodge | Jun 3 | Jun 18 | Sep 19 | 108 |
| Rexford | May 11 | May 25 | Sep 27 | 139 |
| Richey | May 16 | May 31 | Sep 22 | 129 |
| Ronan | May 10 | May 26 | Oct 5 | 148 |
| Roundup | May 20 | Jun 2 | Sep 21 | 124 |
| Ryegate | May 17 | May 30 | Sep 23 | 129 |
| Saco | May 15 | May 26 | Sep 23 | 131 |
| Scobey | May 28 | Jun 13 | Sep 6 | 101 |
| Shelby | May 23 | Jun 6 | Sep 16 | 116 |
| Sheridan | May 24 | Jun 13 | Sep 22 | 121 |
| Sidney | May 11 | May 25 | Sep 27 | 139 |
| St. Ignatius | May 12 | Jun 1 | Oct 2 | 143 |
| Stanford | May 25 | Jun 15 | Sep 21 | 119 |
| Stevensville | May 22 | Jun 13 | Sep 19 | 120 |
| Sunburst | May 17 | May 31 | Sep 25 | 131 |
| Superior | May 17 | Jun 8 | Sep 23 | 129 |
| Terry | May 12 | May 25 | Sep 28 | 139 |
| Thompson Falls | May 7 | May 19 | Oct 4 | 150 |
| Three Forks | May 9 | May 24 | Sep 27 | 141 |
| Townsend | May 19 | Jun 2 | Sep 19 | 123 |
| Troy | May 14 | May 31 | Sep 25 | 134 |
| Twin Bridges | Jun 8 | Jul 1 | Sep 2 | 86 |
| Valier | May 17 | May 31 | Sep 24 | 130 |
| Virginia City | Jun 4 | Jun 23 | Sep 18 | 106 |
| Walkerville | Jun 13 | Jul 1 | Sep 5 | 84 |
| West Yellowstone | Frost possible any month | |||
| Westby | May 18 | May 30 | Sep 21 | 126 |
| White Sulphur Springs | Jun 4 | Jun 20 | Sep 11 | 99 |
| Whitefish | May 16 | Jun 6 | Sep 25 | 132 |
| Whitehall | Jun 13 | Jul 1 | Sep 5 | 84 |
| Wibaux | May 27 | Jun 13 | Sep 16 | 112 |
| Winifred | May 16 | May 30 | Sep 23 | 130 |
| Winnett | May 18 | May 31 | Sep 21 | 126 |
| Wolf Point | May 8 | May 20 | Sep 28 | 143 |
Source: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020. City centers from the US Census Bureau. Click a city for its nearest station and, where it has frost dates, hard-freeze dates and a vegetable planting calendar. See how we calculate.
Frequently asked questions
When is the last frost in Billings, MT?
The average last spring frost in Billings is May 5, and only 1 year in 10 has a frost after May 21. The average first fall frost is October 3. These come from NOAA's 1991–2020 records at the Billings WFO station.
When should I plant tomatoes in Montana?
UNH Extension times tomato transplants for 1 to 2 weeks after the average last frost. In Billings that's about May 12 to May 19; for a 9 in 10 chance of no later frost, wait until May 21. Look up your ZIP code for your own dates and a full vegetable planting calendar.
More for Montana: Montana climate zones (insulation) · Montana planting zones · Frost line depth by state