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.
Soil Temperature in Colorado
The current average 2-inch soil temperature across Colorado is 59°F. Readings range from 48°F to 67°F, from 8 USDA and NOAA monitoring stations. Soil across Colorado is right at the seasonal normal of 60°F for early October, based on 8 of 8 stations with historical records. Colorado spans USDA hardiness zones 4b to 7a, cool-season grass country. Last updated September 30, 2026.
Current Planting Conditions
Prime fall conditions across Colorado with soil averaging 59°F at 2 inches. This is the best seeding window of the year for tall fescue and Kentucky bluegrass, and the main fall feeding window for cool-season lawns.
Best Time to Plant Grass Seed in Colorado
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.
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 30, 2026: Colorado averages 59°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.
Average Soil Temperature by Month in Colorado
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 in Colorado
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 |
Monitoring Stations in Colorado (8)
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) | 61°F | 2026-09-30 |
| CPER (Weld) | 67°F | 2026-09-30 |
| Montrose 11 ENE | 53°F | 2026-09-30 |
| Cortez 8 SE | 54°F | 2026-09-30 |
| La Junta 17 WSW | 64°F | 2026-09-30 |
| Nunn 7 NNE | 62°F | 2026-09-30 |
| Boulder 14 W | 48°F | 2026-09-30 |
| Dinosaur 2 E | 60°F | 2026-09-30 |
Soil Temperature by Region in Colorado
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) | 64°F | 61–67°F | 3 |
| Central Colorado | 54°F | 48–62°F | 3 |
| Western Colorado | 57°F | 54–60°F | 2 |
Cities in Colorado (46)
| City | ZIP | Current Temp |
|---|---|---|
| Alamosa | 81101 | 56°F |
| Arvada | 80001 | 48°F |
| Aspen | 81611 | 53°F |
| Aurora | 80010 | 48°F |
| Boulder | 80301 | 48°F |
| Brighton | 80601 | 48°F |
| Broomfield | 80020 | 48°F |
| Canon City | 81212 | 64°F |
| Castle Rock | 80104 | 48°F |
| Colorado Springs | 80901 | 64°F |
| Commerce City | 80022 | 48°F |
| Craig | 81625 | 60°F |
| Crested Butte | 81224 | 53°F |
| Crowley | 81033 | 64°F |
| Denver | 80201 | 48°F |
| Dinosaur | 81610 | 60°F |
| Durango | 81301 | 54°F |
| Englewood | 80110 | 48°F |
| Estes Park | 80511 | 48°F |
| Evergreen | 80437 | 48°F |
| Florence | 81226 | 64°F |
| Fort Collins | 80521 | 62°F |
| Glenwood Springs | 81601 | 53°F |
| Golden | 80401 | 48°F |
| Grand Junction | 81501 | 53°F |
| Greeley | 80631 | 62°F |
| Gunnison | 81230 | 53°F |
| Lakewood | — | 48°F |
| Limon | 80826 | 64°F |
| Littleton | 80120 | 48°F |
| Longmont | 80501 | 48°F |
| Louisville | 80027 | 48°F |
| Loveland | 80537 | 48°F |
| Montrose | 81401 | 53°F |
| Pagosa Springs | 81147 | 54°F |
| Parker | 80134 | 48°F |
| Pueblo | 81001 | 64°F |
| Silverthorne | 80497 | 48°F |
| Steamboat Springs | 80477 | 48°F |
| Thornton | 80241 | 48°F |
| U S A F Academy | 80840 | 64°F |
| Vail | 81657 | 48°F |
| Westminster | 80030 | 48°F |
| Wheat Ridge | 80033 | 48°F |
| Windsor | 80550 | 62°F |
| Woodland Park | 80863 | 48°F |
Lawn Care Timing Guides for Colorado
- When to Overseed Your Lawn in Fall: The 60-70°F Soil Window
Fall is the best time to overseed a thin lawn.
- Fall Broadleaf Weed Control: The Best Kill Window of the Year
Fall is when broadleaf herbicide works hardest.
- When to Apply Winterizer: Late-Fall Nitrogen Timing by Soil Temperature
Apply winterizer when your 2-inch soil temperature falls through 50°F, typically late October to mid-November for cool-season lawns.
- When to Apply Pre-Emergent in Fall: Stop Poa Annua at 70°F
Time fall pre-emergent ahead of poa annua germination.
Soil Temperature FAQ for Colorado
What is the current soil temperature in Colorado?
The current average 2-inch soil temperature across Colorado is 59°F. Readings range from 48°F to 67°F depending on location and elevation, from 8 USDA and NOAA monitoring stations. Soil across Colorado is right at the seasonal normal of 60°F for early October, based on 8 of 8 stations with historical records.
When should I apply pre-emergent in Colorado?
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.
When can I plant grass seed in Colorado?
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.
