St. Clair, MI Weather & Growing Conditions
This Afternoon
66°F
Chance Light Rain
A chance of rain. Cloudy. High near 66, with temperatures falling to around 63 in the afternoon. South wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 30%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 66°F | Chance Light Rain | 15 mph S | 34% |
| Tonight | 52°F | Light Rain Likely then Mostly Cloudy | 8 to 16 mph SSW | 56% |
| Thursday | 60°F | Mostly Cloudy then Slight Chance Light Rain | 8 to 15 mph SW | 15% |
| Thursday Night | 41°F | Light Rain Likely | 6 to 9 mph WSW | 60% |
| Friday | 52°F | Light Rain Likely | 7 to 10 mph WNW | 56% |
| Friday Night | 35°F | Light Rain Likely | 9 to 14 mph NW | 56% |
| Saturday | 51°F | Chance Light Rain | 8 to 14 mph NW | 39% |
| Saturday Night | 30°F | Mostly Cloudy | 3 to 7 mph WNW | 3% |
| Sunday | 57°F | Mostly Sunny | 5 to 12 mph W | 5% |
| Sunday Night | 33°F | Partly Cloudy | 6 to 9 mph W | 5% |
| Monday | 57°F | Mostly Sunny | 5 to 10 mph W | 1% |
| Monday Night | 38°F | Partly Cloudy | 8 mph WSW | 1% |
| Tuesday | 61°F | Sunny | 7 to 10 mph W | 1% |
| Tuesday Night | 34°F | Partly Cloudy | 6 mph WNW | 1% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for St. Clair, MI
Last spring frost
May 3
First fall frost
Oct 18
Growing season
167 days
Hardiness zone
6a
Explore more for St. Clair, MI: full frost dates · planting calendar · Michigan frost dates
Climate data from the nearest NOAA station, Algonac Wwtp, Mi (10.7 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 5, 2026.