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.
Today
84°F
Sunny
Sunny, with a high near 84. South wind around 9 mph.
7-day forecast for St. Clair
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 84°F | Sunny | 9 mph S | 0% |
| Tonight | 59°F | Mostly Clear | 3 to 9 mph S | 0% |
| Wednesday | 86°F | Sunny | 3 to 10 mph SSW | 0% |
| Wednesday Night | 65°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 1 to 8 mph SSW | 17% |
| Thursday | 83°F | Showers And Thunderstorms Likely | 1 to 7 mph WSW | 62% |
| Thursday Night | 63°F | Showers And Thunderstorms Likely then Chance Showers And Thunderstorms | 0 to 5 mph WNW | 62% |
| Friday | 84°F | Chance Showers And Thunderstorms | 0 to 3 mph WSW | 47% |
| Friday Night | 64°F | Chance Showers And Thunderstorms then Partly Cloudy | 0 to 3 mph SSW | 44% |
| Saturday | 87°F | Mostly Sunny | 1 to 8 mph SW | 12% |
| Saturday Night | 66°F | Chance Showers And Thunderstorms | 2 to 6 mph SSW | 31% |
| Sunday | 89°F | Chance Rain Showers | 2 to 12 mph SW | 31% |
| Sunday Night | 67°F | Chance Showers And Thunderstorms | 5 to 10 mph WSW | 44% |
| Monday | 86°F | Chance Rain Showers | 5 to 9 mph W | 44% |
| Monday Night | 65°F | Chance Showers And Thunderstorms | 6 mph WSW | 45% |
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 Aug 4, 2026.