Frost dates
Frost dates in Montana
Typical last spring frost and first fall frost for 216 weather stations across Montana, from NOAA’s 1991–2020 climate normals.
Last spring frost
May 10 – Jun 5
Typical across Montana (middle: May 20)
First fall frost
Sep 8 – Sep 30
Typical across Montana (middle: Sep 21)
Your own yard can differ by weeks from the nearest town. Get frost dates for your exact spot →
By town
| Station | Last spring frost | First fall frost | Frost-free days |
|---|---|---|---|
| Adel | Jun 4 | Sep 12 | 100 |
| Alberton | May 18 | Sep 25 | 130 |
| Albion 1 N | Jun 2 | Sep 6 | 96 |
| Alder 17 S | Jun 6 | Sep 14 | 100 |
| Anaconda | Jun 1 | Sep 14 | 105 |
| Augusta | May 19 | Sep 21 | 125 |
| Austin 1 W | Jun 4 | Sep 14 | 102 |
| Baker | May 12 | Sep 26 | 137 |
| Baker Municipal Airport | May 16 | Sep 26 | 133 |
| Biddle 8 SW | May 14 | Sep 28 | 137 |
| Big Sandy | May 17 | Sep 25 | 131 |
| Big Timber | May 14 | Sep 26 | 135 |
| Bigfork 13 S | May 1 | Oct 15 | 167 |
| Billings | May 5 | Oct 3 | 151 |
| Billings Logan International Airport | May 4 | Oct 7 | 156 |
| Billings Wtp | May 10 | Oct 1 | 144 |
| Blackleaf | Jun 9 | Sep 3 | 86 |
| Boulder | Jun 7 | Sep 8 | 93 |
| Bozeman 6 W Experiment Farm | May 23 | Sep 23 | 123 |
| Bozeman Gallatin Field | May 26 | Sep 16 | 113 |
| Bozeman Montana State Univ | May 26 | Sep 22 | 119 |
| Brady 27 ENE (The Knees) | May 13 | Sep 29 | 139 |
| Brandenberg | May 18 | Sep 22 | 127 |
| Bredette | May 20 | Sep 21 | 124 |
| Bridger 2 N | May 14 | Sep 24 | 133 |
| Broadus | May 16 | Sep 28 | 135 |
| Brockway 3 WSW | May 20 | Sep 19 | 122 |
| Busby | May 23 | Sep 15 | 115 |
| Butte Bert Mooney Airport | Jun 13 | Sep 5 | 84 |
| Bynum 4 SSE | May 16 | Sep 27 | 134 |
| Carlyle 13 NW | May 18 | Sep 29 | 134 |
| Carter 14 W | May 23 | Sep 23 | 123 |
| Cascade 5 S | May 21 | Sep 19 | 121 |
| Chester | May 24 | Sep 17 | 116 |
| Chinook | May 14 | Sep 23 | 132 |
| Chinook 35 SE | May 23 | Sep 23 | 123 |
| Choteau | May 28 | Sep 12 | 107 |
| Choteau 8 NE | May 20 | Sep 22 | 125 |
| Circle | May 17 | Sep 22 | 128 |
| Cohagen | May 25 | Sep 14 | 112 |
| Colstrip | May 15 | Sep 30 | 138 |
| Columbus | May 27 | Sep 14 | 110 |
| Conrad | May 20 | Sep 19 | 122 |
| Content 4 NNE | May 25 | Sep 14 | 112 |
| Creston | May 12 | Sep 25 | 136 |
| Culbertson | May 21 | Sep 20 | 122 |
| Cut Bank Municipal Airport | May 24 | Sep 15 | 114 |
| Darby | May 24 | Sep 23 | 122 |
| Del Bonita | May 28 | Sep 16 | 111 |
| Denton | Jun 1 | Sep 11 | 102 |
| Dillon Airport | Jun 2 | Sep 13 | 103 |
| Dillon U Of Montana Western | Jun 5 | Sep 13 | 100 |
| Divide | Jun 10 | Sep 7 | 89 |
| Dunkirk 19 NNE | May 23 | Sep 14 | 114 |
| E Glacier | Jun 8 | Sep 5 | 89 |
| Ekalaka | May 20 | Sep 23 | 126 |
| Elliston | Jun 9 | Sep 8 | 91 |
| Ennis | Jun 16 | Sep 4 | 80 |
| Eureka RS | May 11 | Sep 27 | 139 |
| Fairfield | May 13 | Sep 27 | 137 |
| Flatwillow 4 ENE | May 16 | Sep 28 | 135 |
| Forsyth | May 9 | Sep 29 | 143 |
| Fort Assiniboine | May 15 | Sep 24 | 132 |
| Fort Belknap 2 SW | May 16 | Sep 22 | 129 |
| Fort Benton | May 15 | Sep 22 | 130 |
| Fort Peck Pwr Plt | May 8 | Oct 1 | 146 |
| Fortine 1 N | May 16 | Sep 18 | 125 |
| Gardiner | May 21 | Sep 27 | 129 |
| Geraldine | May 14 | Sep 26 | 135 |
| Gibson 2 NE | May 27 | Sep 18 | 114 |
| Gibson Dam | Jun 12 | Sep 8 | 88 |
| Gildford | May 24 | Sep 15 | 114 |
| Glasgow #2 | May 3 | Oct 1 | 151 |
| Glasgow International Airport | May 6 | Sep 30 | 147 |
| Glendive | May 3 | Oct 4 | 154 |
| Grass Range | May 20 | Sep 24 | 127 |
| Great Falls | May 12 | Sep 28 | 139 |
| Great Falls 16St | May 6 | Oct 1 | 148 |
| Great Falls International Airport | May 19 | Sep 24 | 128 |
| Hamilton | May 21 | Sep 22 | 124 |
| Hardin | May 13 | Sep 29 | 139 |
| Harlem | May 16 | Sep 21 | 128 |
| Harlem 20 S | May 24 | Sep 22 | 121 |
| Harlowton | May 23 | Sep 16 | 116 |
| Harlowton 11 NW | May 30 | Sep 20 | 113 |
| Havre City County Airport | May 15 | Sep 23 | 131 |
| Hebgen Dam | Jun 15 | Sep 10 | 87 |
| Helena Regional Airport | May 9 | Sep 30 | 144 |
| Heron 2 NW | May 20 | Sep 20 | 123 |
| Highwood 7 NE | May 7 | Oct 2 | 148 |
| Hinsdale 4 SW | May 15 | Sep 26 | 134 |
| Holter Dam | May 19 | Sep 24 | 128 |
| Hungry Horse Dam | May 9 | Oct 1 | 145 |
| Huntley Experiment Station | May 12 | Sep 25 | 136 |
| Hysham | May 10 | Sep 29 | 142 |
| Hysham 25 SSE | May 26 | Sep 16 | 113 |
| Ingomar 9 E | May 21 | Sep 19 | 121 |
| Joliet | May 29 | Sep 15 | 109 |
| Joplin | May 21 | Sep 19 | 121 |
| Jordan | May 21 | Sep 18 | 120 |
| Jordan Airport | May 18 | Sep 20 | 125 |
| Judith Gap | Jun 1 | Sep 15 | 106 |
| Judith Gap 13 E | Jun 3 | Sep 15 | 104 |
| Kalispell Glacier Airport | May 31 | Sep 10 | 102 |
| Laurin 2 NE | May 24 | Sep 22 | 121 |
| Lewistown | May 14 | Sep 28 | 137 |
| Lewistown 11 ESE | May 19 | Sep 25 | 129 |
| Lewistown 11 SSE | May 31 | Sep 14 | 106 |
| Lewistown 42 WSW | Jun 15 | Sep 4 | 81 |
| Lewistown Municipal Airport | May 23 | Sep 21 | 121 |
| Libby | May 10 | Sep 26 | 139 |
| Libby 1 NE RS | May 23 | Sep 21 | 121 |
| Libby Dam (Base) | May 11 | Oct 1 | 143 |
| Lima | Jun 11 | Sep 10 | 91 |
| Lindbergh Lake | May 20 | Sep 22 | 125 |
| Livingston 12 S | May 19 | Sep 25 | 129 |
| Livingston Mission Field | May 27 | Sep 14 | 110 |
| Logan Landfill | May 26 | Sep 15 | 112 |
| Loma | May 20 | Sep 19 | 122 |
| Malta | May 10 | Sep 29 | 142 |
| Malta 35 S | May 16 | Sep 23 | 130 |
| Malta 7 E | May 7 | Sep 28 | 144 |
| Martinsdale 3 NNW | Jun 3 | Sep 8 | 97 |
| Medicine Lake 3 SE | May 16 | Sep 18 | 125 |
| Melstone | May 10 | Sep 29 | 142 |
| Melville 4 W | Jun 9 | Sep 7 | 90 |
| Mildred 5 N | May 20 | Sep 22 | 125 |
| Miles City F Wiley Field | May 8 | Sep 30 | 145 |
| Millegan 14 SE | Jun 11 | Sep 6 | 87 |
| Missoula 2 NE | May 10 | Oct 1 | 144 |
| Missoula 6 NW | May 6 | Oct 4 | 151 |
| Missoula International Airport | May 16 | Sep 26 | 133 |
| Mizpah 4 NNW | May 22 | Sep 15 | 116 |
| Moccasin Experiment Station | May 28 | Sep 20 | 115 |
| Moorhead 9 NE | May 17 | Sep 22 | 128 |
| Mosby 4 ENE | May 5 | Oct 4 | 152 |
| Mystic Lake | Jun 5 | Sep 14 | 101 |
| Nashua #2 | May 12 | Sep 24 | 135 |
| Neihart 8 NNW | Jun 6 | Sep 12 | 98 |
| Norris Madison Pwr House | Apr 30 | Oct 10 | 163 |
| Nye #2 | Jun 1 | Sep 11 | 102 |
| Opheim 10 N | Jun 1 | Sep 7 | 98 |
| Opheim 12 SSE | Jun 5 | Sep 2 | 89 |
| Plentywood | May 25 | Sep 14 | 112 |
| Plevna | May 21 | Sep 20 | 122 |
| Polson | May 10 | Oct 5 | 148 |
| Pompeys Pillar 15 N | May 22 | Sep 22 | 123 |
| Port Of Morgan | May 19 | Sep 22 | 126 |
| Powderville 8 NNE | May 13 | Sep 25 | 135 |
| Rapelje | May 24 | Sep 21 | 120 |
| Raymond Border Station | May 19 | Sep 23 | 127 |
| Raynesford 2 NNW | May 22 | Sep 23 | 124 |
| Red Lodge | Jun 3 | Sep 19 | 108 |
| Redstone | May 28 | Sep 7 | 102 |
| Ridgeway 1 S | May 17 | Sep 22 | 128 |
| Rock Springs | May 15 | Sep 25 | 133 |
| Rogers Pass 9 NNE | May 21 | Sep 15 | 117 |
| Roundup | May 20 | Sep 21 | 124 |
| Roundup 15 SW | May 22 | Sep 15 | 116 |
| Roy 8 NE | May 14 | Sep 24 | 133 |
| Rudyard 19 S | May 23 | Sep 19 | 119 |
| Rudyard 21 N | May 30 | Sep 11 | 104 |
| Ryegate | May 17 | Sep 23 | 129 |
| Ryegate 18 NNW | May 26 | Sep 18 | 115 |
| Saco 1 NNW | May 15 | Sep 23 | 131 |
| Saint Ignatius | May 12 | Oct 2 | 143 |
| Sand Creek | May 12 | Sep 27 | 138 |
| Savage | May 12 | Sep 25 | 136 |
| Scobey 4 NW | May 28 | Sep 6 | 101 |
| Shelby | May 23 | Sep 16 | 116 |
| Shonkin 7 S | May 24 | Sep 21 | 120 |
| Sidney | May 11 | Sep 27 | 139 |
| Simpson 6 N - Wildhorse | May 26 | Sep 15 | 112 |
| Skq Dam | May 15 | Sep 28 | 136 |
| Sonnette 7 SW | May 25 | Sep 19 | 117 |
| St Marie | May 13 | Sep 27 | 137 |
| St Mary | Jun 12 | Sep 5 | 85 |
| St. Mary 1 SSW | Jun 3 | Sep 8 | 97 |
| Stanford | May 25 | Sep 21 | 119 |
| Stevensville | May 22 | Sep 19 | 120 |
| Sun Rvr 4 S | Jun 2 | Sep 10 | 100 |
| Sunburst 8 E | May 17 | Sep 25 | 131 |
| Superior | May 17 | Sep 23 | 129 |
| Swan Lake | May 17 | Sep 19 | 125 |
| Sweetgrass | May 15 | Sep 25 | 133 |
| Terry | May 12 | Sep 28 | 139 |
| Terry 21 NNW | May 26 | Sep 17 | 114 |
| Thompson Falls Ph | May 7 | Oct 4 | 150 |
| Tiber Dam | May 16 | Sep 23 | 130 |
| Tizer Gardens | Jun 18 | Sep 5 | 79 |
| Townsend 3 SE | May 19 | Sep 19 | 123 |
| Trident | May 9 | Sep 27 | 141 |
| Trout Creek RS | May 20 | Sep 21 | 124 |
| Troy | May 14 | Sep 25 | 134 |
| Turner 11 N | May 19 | Sep 21 | 125 |
| Twin Bridges | Jun 8 | Sep 2 | 86 |
| Valentine | May 18 | Sep 21 | 126 |
| Valier | May 17 | Sep 24 | 130 |
| Vida 6 NE | May 16 | Sep 22 | 129 |
| Virginia City | Jun 4 | Sep 18 | 106 |
| W Glacier | May 18 | Sep 20 | 125 |
| Westby | May 18 | Sep 21 | 126 |
| Western Ag Rsch Ctr | May 23 | Sep 21 | 121 |
| White Sulphur Springs #2 | Jun 4 | Sep 11 | 99 |
| Whitefish | May 16 | Sep 25 | 132 |
| Wibaux 2 E | May 27 | Sep 16 | 112 |
| Wilsall 1 S | Jun 4 | Sep 6 | 94 |
| Wilsall 8 ENE | Jun 8 | Sep 7 | 91 |
| Winifred | May 16 | Sep 23 | 130 |
| Wolf Point 29 ENE | May 24 | Sep 14 | 113 |
| Wolf Point 34 NE | May 13 | Sep 28 | 138 |
| Wolf Point International Airport | May 16 | Sep 20 | 127 |
| Wolf Pt | May 8 | Sep 28 | 143 |
| Wyola 1 SW | May 21 | Sep 17 | 119 |
| Yellowtail Dam | May 7 | Oct 5 | 151 |
| Zortman | May 18 | Sep 23 | 128 |
Each date is the median: in half of years the frost comes earlier, in half later. Frost here means a low of 32°F or colder at the station. Low spots and valleys often frost a week or two earlier than these dates; hillsides and city centers later.
Source: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020. The Field almanac also shows how often frost comes early or late, and a reanalysis reading for your exact location.