Thornton, CO Weather & Growing Conditions
Today
56°F
Partly Sunny
Partly sunny. High near 56, with temperatures falling to around 53 in the afternoon. Northeast wind 3 to 7 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 56°F | Partly Sunny | 3 to 7 mph NE | 12% |
| Tonight | 38°F | Mostly Cloudy | 2 to 6 mph NW | 12% |
| Thursday | 58°F | Sunny | 5 mph S | 0% |
| Thursday Night | 38°F | Partly Cloudy | 3 mph SSW | 1% |
| Friday | 57°F | Mostly Sunny | 5 mph N | 7% |
| Friday Night | 36°F | Mostly Clear | 3 mph W | 7% |
| Saturday | 59°F | Sunny | 5 mph SE | 1% |
| Saturday Night | 36°F | Mostly Clear | 5 mph S | 0% |
| Sunday | 64°F | Sunny | 2 to 6 mph S | 0% |
| Sunday Night | 40°F | Mostly Clear | 5 mph SW | 0% |
| Monday | 64°F | Sunny | 5 mph SE | 0% |
| Monday Night | 39°F | Partly Cloudy | 3 mph WSW | 0% |
| Tuesday | 64°F | Mostly Sunny | 2 mph ESE | 0% |
| Tuesday Night | 41°F | Partly Cloudy | 3 mph W | 1% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Thornton, CO
Last spring frost
May 2
First fall frost
Oct 11
Growing season
160 days
Hardiness zone
6a
Explore more for Thornton, CO: full frost dates · planting calendar · Colorado frost dates
Climate data from the nearest NOAA station, Northglenn, Co (3.7 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.