The current average 2-inch soil temperature across Colorado is 68°F. Readings range from 57°F to 75°F, from 8 USDA and NOAA monitoring stations. Soil across Colorado is running 3°F above the seasonal normal of 64°F for mid-September, based on 8 of 8 stations with historical records. Colorado spans USDA hardiness zones 4b to 7a, cool-season grass country. Last updated September 14, 2026.
Soil across Colorado is cooling off its summer peak at an average of 68°F at 2 inches. The fall poa annua pre-emergent window is in play as readings fall through the 65–70°F band, and cool-season overseeding follows close behind.
Colorado spans both grass families: cool-season lawns are more common toward the cooler, northern parts of the state and at elevation, warm-season lawns toward the warmer south.
For cool-season lawns (fescue, bluegrass, ryegrass), fall is the best time to plant grass seed in Colorado, 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 19.
Spring is the second choice: the window opens when soil first holds 50°F and narrows as soil passes 65°F, typically by June 4.
For warm-season lawns (bermuda, zoysia, St. Augustine), the best time to plant grass seed in Colorado is late spring into early summer, when soil is warming and a full growing season lies ahead. The window opens when 2-inch soil reaches 65°F and keeps rising, and closes as soil cools back through 65°F, typically around September 17.
| Region | Typical spring window opens | Typical fall window opens | Stations |
|---|---|---|---|
| Eastern Colorado | April 9 | September 5 | 3 |
| Central Colorado | May 2 | September 5 | 3 |
| Western Colorado | April 29 | September 13 | 2 |
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 Denver, when to plant in Colorado Springs or when to plant in Aurora. Readings current through September 14, 2026: Colorado averages 68°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 8 monitoring stations in Colorado; your own window depends on your nearest station's readings.
Historical 2-inch soil temperature normals for Colorado: the median across 8 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 | 30°F |
| February | 33°F |
| March | 40°F |
| April | 49°F |
| May | 58°F |
| June | 70°F |
| July | 74°F |
| August | 74°F |
| September | 67°F |
| October | 53°F |
| November | 39°F |
| December | 32°F |
Shaded spring cells fall in the 50°F to 55°F pre-emergent window at 2-inch depth. The highlighted row is the current month.
Grass seed germination
Grass seed germination temperatures across Colorado. 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 | 60–70°F | 14-30 |
| Tall fescue | 60–70°F | 7-12 |
| Perennial ryegrass | 60–70°F | 5-10 |
| Fine fescue | 60–70°F | 7-14 |
| Bermudagrass | 75–90°F | 10-30 |
For root-zone timing (fertilizer, aeration, weed control), see the 4-inch soil temperature for Colorado. For accumulated-heat timing, see growing degree days for Colorado. For how wet the ground is versus normal, see soil moisture for Colorado. See the Colorado soil temperature map for the full station view.
Interpolated from the latest 4-inch readings and refreshed daily.
| Station | 2" Temp | Last Reading |
|---|---|---|
| Nunn #1 (Weld) | 66°F | 2026-09-14 |
| CPER (Weld) | 69°F | 2026-09-14 |
| Montrose 11 ENE | 63°F | 2026-09-14 |
| Cortez 8 SE | 69°F | 2026-09-14 |
| La Junta 17 WSW | 75°F | 2026-09-14 |
| Nunn 7 NNE | 69°F | 2026-09-14 |
| Boulder 14 W | 57°F | 2026-09-14 |
| Dinosaur 2 E | 75°F | 2026-09-14 |
Current 2-inch readings grouped along Colorado'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 Colorado (Weld County) | 70°F | 66–75°F | 3 |
| Central Colorado | 63°F | 57–69°F | 3 |
| Western Colorado | 72°F | 69–75°F | 2 |
| City | ZIP | Current Temp |
|---|---|---|
| Alamosa | 81101 | 63°F |
| Arvada | 80001 | 57°F |
| Aspen | 81611 | 63°F |
| Aurora | 80010 | 57°F |
| Boulder | 80301 | 57°F |
| Brighton | 80601 | 57°F |
| Broomfield | 80020 | 57°F |
| Canon City | 81212 | 75°F |
| Castle Rock | 80104 | 57°F |
| Colorado Springs | 80901 | 75°F |
| Commerce City | 80022 | 57°F |
| Craig | 81625 | 75°F |
| Crested Butte | 81224 | 63°F |
| Crowley | 81033 | 75°F |
| Denver | 80201 | 57°F |
| Dinosaur | 81610 | 75°F |
| Durango | 81301 | 69°F |
| Englewood | 80110 | 57°F |
| Estes Park | 80511 | 57°F |
| Evergreen | 80437 | 57°F |
| Florence | 81226 | 75°F |
| Fort Collins | 80521 | 69°F |
| Glenwood Springs | 81601 | 63°F |
| Golden | 80401 | 57°F |
| Grand Junction | 81501 | 63°F |
| Greeley | 80631 | 69°F |
| Gunnison | 81230 | 63°F |
| Lakewood | — | 57°F |
| Limon | 80826 | 75°F |
| Littleton | 80120 | 57°F |
| Longmont | 80501 | 57°F |
| Louisville | 80027 | 57°F |
| Loveland | 80537 | 57°F |
| Montrose | 81401 | 63°F |
| Pagosa Springs | 81147 | 69°F |
| Parker | 80134 | 57°F |
| Pueblo | 81001 | 75°F |
| Silverthorne | 80497 | 57°F |
| Steamboat Springs | 80477 | 57°F |
| Thornton | 80241 | 57°F |
| U S A F Academy | 80840 | 75°F |
| Vail | 81657 | 57°F |
| Westminster | 80030 | 57°F |
| Wheat Ridge | 80033 | 57°F |
| Windsor | 80550 | 69°F |
| Woodland Park | 80863 | 57°F |
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.
Apply fall pre-emergent when 2-inch soil falls back through 70°F and keeps declining; that crossing is when poa annua and winter annual weeds sprout.
Fall is when broadleaf herbicide works hardest.
The current average 2-inch soil temperature across Colorado is 68°F. Readings range from 57°F to 75°F depending on location and elevation, from 8 USDA and NOAA monitoring stations. Soil across Colorado is running 3°F above the seasonal normal of 64°F for mid-September, based on 8 of 8 stations with historical records.
Apply pre-emergent herbicide when soil at 2 inches reaches 55°F for several consecutive days. Timing varies across Colorado, so check your city's page for station-specific readings and the pre-emergent timing recommendation.
Colorado spans USDA hardiness zones 4b to 7a, cool-season grass country. For cool-season grasses (fescue, bluegrass), the fall window typically opens around September 5 and the spring window around April 11; for warm-season grasses (bermuda, zoysia), the window typically opens around June 4, based on historical 2-inch soil temperature averages at 8 in-state stations. Timing varies by location, so check your city's planting window for the dates specific to your area.