Colorado · 12 cities · spring 2026

When to apply crabgrass preventer in Colorado

Last spring the soil reached 50°F aroundMar 19Median of 12 cities; crabgrass temperatures (55°F) followed around Mar 21. Earliest: Pueblo Feb 27; latest: Castle Rock Mar 21.
Today
Season over
12 of 12 cities
Window last spring
2 days
median gap from 50°F to 55°F
Soil today
51°F
median, 0–4 in
Never below 50°F
0
cities with no spring window

Last spring's pre-emergent window, largest Colorado cities

Each bar runs from the day the soil held 50°F to the day it held 55°F (2026).

FebMarAprMayDenverDenver: Mar 12 to Mar 20Colorado SpringsColorado Springs: Mar 20 to Mar 21Fort CollinsFort Collins: Mar 19 to Mar 20PuebloPueblo: Feb 27 to Mar 19GreeleyGreeley: Mar 19 to Mar 21BoulderBoulder: Mar 20 to Mar 21Grand JunctionGrand Junction: Mar 11 to Mar 19Castle RockCastle Rock: Mar 21 to Mar 22BrightonBrighton: Mar 19 to Mar 21MontroseMontrose: Mar 18 to Mar 21DurangoDurango: Mar 19 to Mar 21Cañon CityCañon City: Mar 19 to Mar 21
FebMarAprMayDenverDenver: Mar 12 to Mar 20Colorado Sp…Colorado Springs: Mar 20 to Mar 21Fort CollinsFort Collins: Mar 19 to Mar 20PuebloPueblo: Feb 27 to Mar 19GreeleyGreeley: Mar 19 to Mar 21BoulderBoulder: Mar 20 to Mar 21Grand Junct…Grand Junction: Mar 11 to Mar 19Castle RockCastle Rock: Mar 21 to Mar 22BrightonBrighton: Mar 19 to Mar 21MontroseMontrose: Mar 18 to Mar 21DurangoDurango: Mar 19 to Mar 21Cañon CityCañon City: Mar 19 to Mar 21
Source: NOAA NCEP GFS analyses, 0–10 cm; 5-day mean held 10 days.

Every Colorado city

Spring 2026 dates and today's verdict.

CityHeld 50°F (2026)Held 55°F (2026)Soil todayToday
Denver, COMar 12Mar 2057°FSeason over
Colorado Springs, COMar 20Mar 2152°FSeason over
Fort Collins, COMar 19Mar 2052°FSeason over
Pueblo, COFeb 27Mar 1954°FSeason over
Greeley, COMar 19Mar 2152°FSeason over
Boulder, COMar 20Mar 2150°FSeason over
Grand Junction, COMar 11Mar 1951°FSeason over
Castle Rock, COMar 21Mar 2247°FSeason over
Brighton, COMar 19Mar 2151°FSeason over
Montrose, COMar 18Mar 2146°FSeason over
Durango, COMar 19Mar 2144°FSeason over
Cañon City, COMar 19Mar 2150°FSeason over

Crabgrass seeds start to germinate once the top 2 to 4 inches of soil stay near 55°F for several days. A pre-emergent works as a barrier in the soil, so it has to be down and watered in before that: the usual advice is to apply it while the soil holds 50 to 55°F. The dates here are when the modelled soil began to hold each temperature last spring; this year's window will move with the weather, which is why each city page shows today's reading and the 7-day forecast.

Questions

When should I put down crabgrass preventer in Colorado?
When the soil holds 50 to 55°F. Last spring that was around Mar 19 to Mar 21 across 12 Colorado cities, earlier in the south and in cities.
Is it too late to apply pre-emergent?
Once the soil has held 55°F for a week or more, crabgrass is germinating and a pre-emergent will not stop the seedlings already up. Each city page says which side of that line it is on today.

Soil temperature today in Colorado →

Data: Global Forecast System (GFS) 0.25°, soil temperature 0–10 cm (TSOIL) (NOAA National Centers for Environmental Prediction (NCEP)); GeoNames gazetteer (cities15000) (GeoNames).