St. Clair, MI Weather & Growing Conditions
Today
68°F
Chance Rain Showers
A chance of rain showers before 5pm, then a chance of showers and thunderstorms. Cloudy. High near 68, with temperatures falling to around 64 in the afternoon. Southeast wind around 8 mph. Chance of precipitation is 50%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 68°F | Chance Rain Showers | 8 mph SE | 50% |
| Tonight | 56°F | Chance Showers And Thunderstorms | 7 mph E | 84% |
| Sunday | 68°F | Rain Showers Likely | 5 to 14 mph NNE | 57% |
| Sunday Night | 49°F | Mostly Cloudy | 7 to 14 mph NNE | 1% |
| Monday | 64°F | Partly Sunny | 8 to 12 mph NE | 1% |
| Monday Night | 46°F | Mostly Cloudy | 10 mph NE | 3% |
| Tuesday | 64°F | Partly Sunny | 10 to 14 mph ENE | 9% |
| Tuesday Night | 48°F | Chance Rain Showers | 10 to 14 mph ENE | 39% |
| Wednesday | 63°F | Chance Rain Showers | 14 mph E | 47% |
| Wednesday Night | 49°F | Chance Rain Showers | 6 to 12 mph E | 39% |
| Thursday | 65°F | Slight Chance Rain Showers | 9 mph ENE | 24% |
| Thursday Night | 49°F | Mostly Cloudy | 3 to 7 mph NE | 13% |
| Friday | 69°F | Mostly Sunny | 3 to 9 mph NE | 8% |
| Friday Night | 49°F | Partly Cloudy | 3 to 8 mph NE | 7% |
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 Sep 19, 2026.