Montana frost dates
The typical last spring frost ranges from May 10 in Billings to Jun 15 in West Yellowstone.
5 of the 6 Montana cities listed have typical frost dates. The longest frost-free season is 143 days in Missoula; the shortest is 87 days in West Yellowstone. For a single address, look up your ZIP code: rural ZIPs use their nearest suitable station.
| City | Last spring frost | 1 in 10 after | First fall frost | 1 in 10 before | Hard freeze (28°F) | Season |
|---|---|---|---|---|---|---|
| Big Sky | not available for this location | |||||
| Billings | May 10 | May 24 | Oct 1 | Sep 19 | Apr 27 / Oct 12 | 142 days |
| Great Falls | May 19 | Jun 2 | Sep 24 | Sep 9 | May 5 / Oct 3 | 126 days |
| Missoula | May 10 | May 28 | Oct 1 | Sep 16 | Apr 28 / Oct 12 | 143 days |
| West Yellowstone | Jun 15 | Jul 7 | Sep 10 | Aug 25 | May 24 / Sep 26 | 87 days |
| Whitefish | May 16 | Jun 6 | Sep 25 | Sep 8 | May 1 / Oct 7 | 129 days |
Reading the table: Whitefish
In Whitefish, the last spring frost typically comes around May 16: in half of years it is earlier, in half later. In 1 year in 10 it comes after Jun 6, 21 days later, so tender plants set out after that date have a 90% chance of escaping frost. In fall, the first frost typically arrives around Sep 25, and in 1 year in 10 before Sep 8. Hard freezes (28°F) usually end earlier in spring and start later in fall: around May 1 and Oct 7 in Whitefish.
Frost dates at more Montana weather stations
NOAA stations across Montana used by our ZIP code lookup, named for the town they are in.
| Station | Elevation | Last spring frost | First fall frost |
|---|---|---|---|
| Alberton | 3,060 ft | May 18 (1 in 10 after Jun 6) | Sep 25 (before Sep 7) |
| Baker Muni Airport | 2,971 ft | May 16 (1 in 10 after May 29) | Sep 26 (before Sep 11) |
| Biddle 8 Sw | 3,631 ft | May 14 (1 in 10 after May 27) | Sep 28 (before Sep 13) |
| Big Timber | 4,100 ft | May 14 (1 in 10 after May 27) | Sep 26 (before Sep 10) |
| Bigfork 13 S | 2,979 ft | May 1 (1 in 10 after May 16) | Oct 15 (before Sep 30) |
| Billings Logan Intl Airport | 3,581 ft | May 4 (1 in 10 after May 18) | Oct 7 (before Sep 26) |
| Blackleaf | 4,235 ft | Jun 9 (1 in 10 after Jul 2) | Sep 3 (before Aug 19) |
| Boulder | 4,904 ft | Jun 7 (1 in 10 after Jun 25) | Sep 8 (before Aug 25) |
| Broadus | 3,032 ft | May 16 (1 in 10 after May 29) | Sep 28 (before Sep 13) |
| Busby | 3,430 ft | May 23 (1 in 10 after Jun 7) | Sep 15 (before Sep 1) |
| Butte Bert Mooney Airport | 5,506 ft | Jun 13 (1 in 10 after Jul 1) | Sep 5 (before Aug 24) |
| Carter 14 W | 3,450 ft | May 23 (1 in 10 after Jun 9) | Sep 23 (before Sep 8) |
| Chester | 3,132 ft | May 24 (1 in 10 after Jun 9) | Sep 17 (before Sep 3) |
| Chinook | 2,420 ft | May 14 (1 in 10 after May 27) | Sep 23 (before Sep 11) |
| Chinook 35SE | 3,360 ft | May 23 (1 in 10 after Jun 3) | Sep 23 (before Sep 11) |
| Cohagen | 2,720 ft | May 25 (1 in 10 after Jun 9) | Sep 14 (before Aug 31) |
| Columbus | 3,602 ft | May 27 (1 in 10 after Jun 12) | Sep 14 (before Sep 1) |
| Conrad | 3,550 ft | May 20 (1 in 10 after Jun 3) | Sep 19 (before Sep 4) |
| Creston | 2,935 ft | May 12 (1 in 10 after May 26) | Sep 25 (before Sep 9) |
| Culbertson | 1,940 ft | May 21 (1 in 10 after Jun 3) | Sep 20 (before Sep 6) |
| Darby | 3,880 ft | May 24 (1 in 10 after Jun 14) | Sep 23 (before Sep 4) |
| Denton | 3,610 ft | Jun 1 (1 in 10 after Jun 26) | Sep 11 (before Aug 29) |
| E Glacier | 4,806 ft | Jun 8 (1 in 10 after Jul 1) | Sep 5 (before Aug 20) |
| Elliston | 5,080 ft | Jun 9 (1 in 10 after Jun 26) | Sep 8 (before Aug 26) |
| Fairfield | 3,983 ft | May 13 (1 in 10 after Jun 1) | Sep 27 (before Sep 14) |
| Forsyth | 2,515 ft | May 9 (1 in 10 after May 21) | Sep 29 (before Sep 16) |
| Fortine 1 N | 3,000 ft | May 16 (1 in 10 after Jun 3) | Sep 18 (before Sep 1) |
| Gibson Dam | 4,590 ft | Jun 12 (1 in 10 after Jul 5) | Sep 8 (before Aug 23) |
| Gildford | 2,820 ft | May 24 (1 in 10 after Jun 7) | Sep 15 (before Aug 29) |
| Glasgow Intl Airport | 2,285 ft | May 6 (1 in 10 after May 18) | Sep 30 (before Sep 17) |
| Glendive | 2,075 ft | May 3 (1 in 10 after May 16) | Oct 4 (before Sep 22) |
| Helena Rgnl Airport | 3,828 ft | May 9 (1 in 10 after May 25) | Sep 30 (before Sep 17) |
| Hungry Horse Dam | 3,160 ft | May 9 (1 in 10 after May 30) | Oct 1 (before Sep 13) |
| Huntley Exp Stn | 3,034 ft | May 12 (1 in 10 after May 26) | Sep 25 (before Sep 13) |
| Hysham | 2,669 ft | May 10 (1 in 10 after May 22) | Sep 29 (before Sep 15) |
| Joliet | 3,838 ft | May 29 (1 in 10 after Jun 17) | Sep 15 (before Sep 1) |
| Judith Gap | 4,630 ft | Jun 1 (1 in 10 after Jun 16) | Sep 15 (before Aug 31) |
| Lewistown 11ESE | 5,028 ft | May 19 (1 in 10 after Jun 1) | Sep 25 (before Sep 11) |
| Lima | 6,279 ft | Jun 11 (1 in 10 after Jun 30) | Sep 10 (before Aug 27) |
| Lindbergh Lake | 4,320 ft | May 20 (1 in 10 after Jun 7) | Sep 22 (before Sep 5) |
| Loma | 2,578 ft | May 20 (1 in 10 after Jun 3) | Sep 19 (before Sep 4) |
| Medicine Lake 3 Se | 1,942 ft | May 16 (1 in 10 after May 30) | Sep 18 (before Sep 7) |
| Melstone | 2,932 ft | May 10 (1 in 10 after May 23) | Sep 29 (before Sep 14) |
| Melville 4 W | 5,365 ft | Jun 9 (1 in 10 after Jun 27) | Sep 7 (before Aug 21) |
| Miles City F Wiley Fld | 2,624 ft | May 8 (1 in 10 after May 21) | Sep 30 (before Sep 17) |
| Mosby 4 Ene | 2,910 ft | May 5 (1 in 10 after May 26) | Oct 4 (before Sep 22) |
| Neihart 8 Nnw | 5,230 ft | Jun 6 (1 in 10 after Jun 28) | Sep 12 (before Aug 29) |
| Norris Madison Pwr House | 4,745 ft | Apr 30 (1 in 10 after May 14) | Oct 10 (before Sep 27) |
| Opheim 12 Sse | 2,936 ft | Jun 5 (1 in 10 after Jun 23) | Sep 2 (before Aug 15) |
| Plentywood | 2,048 ft | May 25 (1 in 10 after Jun 8) | Sep 14 (before Sep 2) |
| Plevna | 2,780 ft | May 21 (1 in 10 after Jun 4) | Sep 20 (before Sep 5) |
| Polson | 3,010 ft | May 10 (1 in 10 after May 26) | Oct 5 (before Sep 22) |
| Pompeys Pillar 15N | 3,390 ft | May 22 (1 in 10 after Jun 7) | Sep 22 (before Sep 7) |
| Saint Ignatius | 2,915 ft | May 12 (1 in 10 after Jun 1) | Oct 2 (before Sep 19) |
| Sidney | 1,933 ft | May 11 (1 in 10 after May 25) | Sep 27 (before Sep 13) |
| Stevensville | 3,375 ft | May 22 (1 in 10 after Jun 13) | Sep 19 (before Sep 3) |
| Sun Rvr 4 S | 3,600 ft | Jun 2 (1 in 10 after Jun 21) | Sep 10 (before Aug 25) |
| Sunburst 8 E | 3,700 ft | May 17 (1 in 10 after May 31) | Sep 25 (before Sep 9) |
| Townsend 3SE | 3,964 ft | May 19 (1 in 10 after Jun 2) | Sep 19 (before Sep 5) |
| Twin Bridges | 4,625 ft | Jun 8 (1 in 10 after Jul 1) | Sep 2 (before Aug 16) |
32°F dates from NOAA 1991-2020 freeze probabilities for each city's station. "1 in 10 after": a 10% chance of a later spring frost (planting is 90% safe after it). How to read frost dates.