The current average 2-inch soil temperature across Montana is 66°F. Readings range from 60°F to 71°F, from 13 USDA and NOAA monitoring stations. Soil across Montana is running 5°F below the seasonal normal of 71°F for mid-August, based on 13 of 13 stations with historical records. Montana spans USDA hardiness zones 4b to 5b, cool-season grass country. Last updated August 16, 2026.
Summer conditions across Montana with soil averaging 66°F at 2 inches. Warm-season grasses are in peak growth; keep cool-season lawns mowed high and watered deep. The next application windows arrive in fall, starting with pre-emergent as soil falls back through 70°F.
For cool-season lawns (fescue, bluegrass, ryegrass), fall is the best time to plant grass seed in Montana, with spring the second choice: fall seedlings face less weed competition and mature before summer heat. The window opens as 2-inch soil falls back through 70°F, and germination slows sharply once soil drops below 50°F, typically around October 11.
Spring is the second choice: the window opens when soil first holds 50°F and narrows as soil passes 65°F, typically by June 9.
| Region | Typical spring window opens | Typical fall window opens | Stations |
|---|---|---|---|
| Eastern Montana | May 3 | August 7 | 5 |
| Central Montana | May 3 | August 5 | 5 |
| Western Montana | May 4 | August 4 | 3 |
Fall seeding also needs a stop date: new seedlings want about six weeks of growth before frost arrives. Your city page estimates the last safe seeding date from its nearest station: see when to plant in Billings, when to plant in Helena or when to plant in Missoula. Readings current through August 16, 2026: Montana averages 66°F at 2 inches right now; the Current Planting Conditions section above reads that number against the season.
Typical dates are computed from historical 2-inch soil temperature averages at 13 monitoring stations in Montana; your own window depends on your nearest station's readings.
Historical 2-inch soil temperature normals for Montana: the median across 13 in-state stations with multi-year records. Any given year runs ahead of or behind these values; the live average at the top of this page shows where this year stands.
| Month | Average 2-inch soil temperature |
|---|---|
| January | 26°F |
| February | 28°F |
| March | 33°F |
| April | 42°F |
| May | 53°F |
| June | 63°F |
| July | 70°F |
| August | 69°F |
| September | 61°F |
| October | 47°F |
| November | 36°F |
| December | 30°F |
Grass seed germination
Grass seed germination temperatures across Montana. Soil warmth varies by location, so check a city page for the live reading and what germinates there now.
| Grass species | Seeding soil temp (2 in) | Days |
|---|---|---|
| Kentucky bluegrass | 50–65°F | 14-30 |
| Tall fescue | 50–65°F | 7-12 |
| Perennial ryegrass | 50–65°F | 5-10 |
| Fine fescue | 50–65°F | 7-14 |
| Bermudagrass | 75–90°F | 10-30 |
For root-zone timing (fertilizer, aeration, weed control), see the 4-inch soil temperature for Montana. For accumulated-heat timing, see growing degree days for Montana. For how wet the ground is versus normal, see soil moisture for Montana. See the Montana soil temperature map for the full station view.
Interpolated from the latest 4-inch readings and refreshed daily.
| Station | 2" Temp | Last Reading |
|---|---|---|
| Fort Assiniboine #1 (Hill) | 66°F | 2026-08-16 |
| Conrad Ag Rc (Pondera) | 64°F | 2026-08-16 |
| Violett (Liberty) | 66°F | 2026-08-16 |
| Moccasin (Judith Basin) | 68°F | 2026-08-16 |
| Sidney (Richland) | 68°F | 2026-08-16 |
| Jordan (Garfield) | 68°F | 2026-08-16 |
| Lindsay (Dawson) | 66°F | 2026-08-16 |
| Table Mountain (Gallatin) | 67°F | 2026-08-16 |
| St. Mary 1 SSW | 63°F | 2026-08-16 |
| Dillon 18 WSW | 60°F | 2026-08-15 |
| Lewistown 42 WSW | 67°F | 2026-08-16 |
| Wolf Point 34 NE | 68°F | 2026-08-16 |
| Wolf Point 29 ENE | 71°F | 2026-08-16 |
Current 2-inch readings grouped along Montana's east-to-west axis. Regional spread matters for timing: the warm end of the state can open an application window a week or more before the cool end.
| Region | Avg 2" Temp | Range | Stations |
|---|---|---|---|
| Eastern Montana (Dawson, Garfield, Richland Counties) | 68°F | 66–71°F | 5 |
| Central Montana (Gallatin, Hill, Judith Basin, Liberty Counties) | 67°F | 66–68°F | 5 |
| Western Montana (Pondera County) | 62°F | 60–64°F | 3 |
| City | ZIP | Current Temp |
|---|---|---|
| Ashland | 59003 | 77°F* |
| Billings | 59101 | 79°F* |
| Bozeman | 59715 | 67°F |
| Butte | 59701 | 67°F |
| Great Falls | 59401 | 64°F |
| Helena | 59601 | 67°F |
| Kalispell | 59901 | 63°F |
| Missoula | 59801 | 72°F* |
| Roundup | 59072 | 74°F* |
Modeled estimate where no monitoring station is within 75 miles; all other readings are measured at USDA and NOAA stations.
Fall is the best time to overseed a thin lawn.
Core aeration relieves compaction, but timing decides whether the lawn recovers in a week or struggles for a month.
Brown patch and Pythium strike when humid nights hold above 68°F on lush, over-fertilized turf; dollar spot, red thread, and rust hit slow-growing lawns at 60-85°F.
Check whether your soil is warm enough for the seed you bought: cool-season grass seeds into 50-65°F soil (tall fescue prefers 60°F and up), warm-season into 75-85°F.
The current average 2-inch soil temperature across Montana is 66°F. Readings range from 60°F to 71°F depending on location and elevation, from 13 USDA and NOAA monitoring stations. Soil across Montana is running 5°F below the seasonal normal of 71°F for mid-August, based on 13 of 13 stations with historical records.
Apply pre-emergent herbicide when soil at 2 inches reaches 55°F for several consecutive days. Timing varies across Montana, so check your city's page for station-specific readings and the pre-emergent timing recommendation.
Montana spans USDA hardiness zones 4b to 5b, cool-season grass country. For cool-season grasses (fescue, bluegrass), the fall window typically opens around August 5 and the spring window around May 3, based on historical 2-inch soil temperature averages at 13 in-state stations. Timing varies by location, so check your city's planting window for the dates specific to your area.