St. Mary's, CO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Mary's, a community in Clear Creek County, Colorado.
Overnight
22°F
Partly Cloudy
Partly cloudy, with a low around 22. West northwest wind around 10 mph, with gusts as high as 17 mph.
7-day forecast for St. Mary's
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 22°F | Partly Cloudy | 10 mph WNW | 0% |
| Wednesday | 31°F | Chance Snow Showers | 8 to 13 mph SE | 52% |
| Wednesday Night | 20°F | Chance Snow Showers | 5 to 10 mph WSW | 52% |
| Thursday | 33°F | Sunny | 3 to 12 mph SE | 0% |
| Thursday Night | 24°F | Mostly Cloudy | 3 to 13 mph SW | 4% |
| Friday | 32°F | Chance Snow Showers | 3 to 13 mph W | 27% |
| Friday Night | 21°F | Chance Snow Showers then Mostly Clear | 5 to 18 mph W | 26% |
| Saturday | 34°F | Sunny | 2 to 18 mph WNW | 2% |
| Saturday Night | 23°F | Mostly Clear | 5 to 14 mph WNW | 0% |
| Sunday | 41°F | Sunny | 8 to 16 mph WNW | 0% |
| Sunday Night | 28°F | Mostly Clear | 14 to 20 mph W | 0% |
| Monday | 41°F | Sunny | 3 to 15 mph WNW | 0% |
| Monday Night | 28°F | Partly Cloudy | 5 to 13 mph W | 0% |
| Tuesday | 38°F | Mostly Sunny | 7 to 15 mph W | 2% |
Forecast source: National Weather Service (api.weather.gov) for St. Mary's (39.817, -105.647). Updated through the day.
Growing snapshot for St. Mary's
Last spring frost
May 30
First fall frost
Sep 19
Growing season
112 days
Hardiness zone
5b
More local growing data for St. Mary's: nearby ZIP 80436 weather · frost dates · planting calendar · Colorado frost dates
Nearby towns & communities
Blue Valley
Brook Forest
Downieville-Lawson-Dumont
Echo Hills
Empire
Floyd Hill
Georgetown
Pine Valley
Silver Plume
Upper Bear Creek
Upper Witter Gulch
Climate data from the nearest NOAA station, Georgetown, Co (6.1 mi from St. Mary's). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.