St. Clair, MI Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Clair, a city in St. Clair County, Michigan.
This Afternoon
72°F
Mostly Sunny
Mostly sunny. High near 72, with temperatures falling to around 70 in the afternoon. South wind around 14 mph, with gusts as high as 24 mph.
7-day forecast for St. Clair
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 72°F | Mostly Sunny | 14 mph S | 2% |
| Tonight | 61°F | Mostly Cloudy | 10 mph S | 2% |
| Wednesday | 67°F | Light Rain | 9 to 16 mph S | 96% |
| Wednesday Night | 52°F | Light Rain then Mostly Cloudy | 7 to 16 mph SSW | 80% |
| Thursday | 61°F | Mostly Cloudy | 8 to 14 mph SW | 14% |
| Thursday Night | 47°F | Chance Light Rain | 2 to 8 mph WSW | 28% |
| Friday | 56°F | Chance Light Rain | 3 to 8 mph NW | 47% |
| Friday Night | 39°F | Chance Light Rain | 8 mph NW | 47% |
| Saturday | 52°F | Chance Light Rain | 9 mph NW | 26% |
| Saturday Night | 34°F | Partly Cloudy | 6 mph W | 8% |
| Sunday | 55°F | Mostly Sunny | 5 to 9 mph WSW | 13% |
| Sunday Night | 34°F | Partly Cloudy | 7 mph WNW | 13% |
| Monday | 57°F | Mostly Sunny | 6 to 10 mph W | 12% |
| Monday Night | 38°F | Partly Cloudy | 8 mph WSW | 12% |
Forecast source: National Weather Service (api.weather.gov) for St. Clair (42.827, -82.492). Updated through the day.
Growing snapshot for St. Clair
Last spring frost
Apr 19
First fall frost
Nov 3
Growing season
196 days
Hardiness zone
6a
More local growing data for St. Clair: nearby ZIP 48079 weather · frost dates · planting calendar · Michigan frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Port Huron, Mi (10.3 mi from St. Clair). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 3, 2026.