Thornton, CO Weather & Growing Conditions
Today
79°F
Patchy Smoke
Patchy smoke. Mostly sunny. High near 79, with temperatures falling to around 77 in the afternoon. East northeast wind 7 to 10 mph, with gusts as high as 16 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 79°F | Patchy Smoke | 7 to 10 mph ENE | 11% |
| Tonight | 56°F | Patchy Smoke | 6 to 12 mph NNE | 10% |
| Wednesday | 87°F | Patchy Smoke | 6 to 10 mph NE | 0% |
| Wednesday Night | 59°F | Mostly Clear | 5 to 10 mph S | 2% |
| Thursday | 96°F | Sunny | 3 to 8 mph NNW | 0% |
| Thursday Night | 62°F | Mostly Clear | 8 mph S | 2% |
| Friday | 98°F | Sunny | 3 to 9 mph S | 0% |
| Friday Night | 67°F | Mostly Clear | 10 mph S | 0% |
| Saturday | 100°F | Sunny | 5 to 9 mph NNW | 1% |
| Saturday Night | 66°F | Partly Cloudy | 6 to 9 mph W | 0% |
| Sunday | 100°F | Sunny | 3 to 9 mph N | 6% |
| Sunday Night | 67°F | Partly Cloudy | 5 to 9 mph WNW | 4% |
| Monday | 99°F | Sunny then Slight Chance Showers And Thunderstorms | 5 to 12 mph N | 15% |
| Monday Night | 66°F | Mostly Cloudy | 5 to 12 mph WNW | 14% |
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 Aug 4, 2026.