Thornton, CO Weather & Growing Conditions
Overnight
55°F
Mostly Cloudy
Mostly cloudy, with a low around 55. West southwest wind around 3 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 55°F | Mostly Cloudy | 3 mph WSW | 2% |
| Saturday | 76°F | Mostly Sunny then Chance Showers And Thunderstorms | 2 to 8 mph NE | 65% |
| Saturday Night | 51°F | Chance Showers And Thunderstorms then Partly Cloudy | 2 to 8 mph SSW | 41% |
| Sunday | 71°F | Partly Sunny then Chance Showers And Thunderstorms | 2 to 9 mph NNE | 29% |
| Sunday Night | 49°F | Chance Showers And Thunderstorms then Partly Cloudy | 2 to 8 mph NNE | 30% |
| Monday | 73°F | Mostly Sunny | 2 to 10 mph NE | 1% |
| Monday Night | 50°F | Chance Showers And Thunderstorms then Partly Cloudy | 2 to 10 mph SSE | 27% |
| Tuesday | 76°F | Mostly Sunny | 2 to 7 mph NNE | 5% |
| Tuesday Night | 53°F | Partly Cloudy | 3 to 7 mph SSW | 13% |
| Wednesday | 78°F | Mostly Sunny | 3 to 7 mph NE | 7% |
| Wednesday Night | 53°F | Mostly Cloudy | 3 to 7 mph SW | 11% |
| Thursday | 79°F | Mostly Sunny | 2 to 9 mph S | 5% |
| Thursday Night | 55°F | Partly Cloudy | 3 to 9 mph S | 13% |
| Friday | 80°F | Mostly Sunny | 2 to 8 mph S | 10% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Thornton, CO
Last spring frost
May 3
First fall frost
Oct 7
Growing season
155 days
Hardiness zone
6a
Explore more for Thornton, CO: full frost dates · planting calendar · Colorado frost dates
Climate data from the nearest NOAA station, Brighton 3 Se, Co (4.2 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.