St. Clair, MN Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Clair, a city in Blue Earth County, Minnesota.
Tonight
59°F
Patchy Fog
Patchy fog and showers and thunderstorms before 10pm, then patchy fog and a chance of showers and thunderstorms between 10pm and 4am, then a chance of showers and thunderstorms. Some of the storms could produce heavy rain. Cloudy, with a low around 59. East wind 10 to 15 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.
7-day forecast for St. Clair
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 59°F | Patchy Fog | 10 to 15 mph E | 88% |
| Saturday | 65°F | Chance Showers And Thunderstorms then Slight Chance T-storms | 10 mph NE | 36% |
| Saturday Night | 55°F | Slight Chance Drizzle then Mostly Cloudy | 10 mph NNE | 19% |
| Sunday | 66°F | Mostly Cloudy | 10 to 15 mph NE | 4% |
| Sunday Night | 50°F | Mostly Cloudy | 10 mph ENE | 14% |
| Monday | 61°F | Chance Rain Showers | 10 mph ENE | 37% |
| Monday Night | 46°F | Chance Rain Showers then Mostly Cloudy | 5 to 10 mph ENE | 37% |
| Tuesday | 62°F | Partly Sunny | 5 to 10 mph E | 6% |
| Tuesday Night | 44°F | Partly Cloudy | 5 mph ESE | 0% |
| Wednesday | 66°F | Sunny | 5 mph SE | 0% |
| Wednesday Night | 49°F | Partly Cloudy | 0 to 5 mph SSE | 10% |
| Thursday | 68°F | Mostly Sunny | 0 to 5 mph SSE | 14% |
| Thursday Night | 52°F | Partly Cloudy | 0 to 5 mph SSE | 6% |
| Friday | 69°F | Mostly Sunny | 5 mph SE | 7% |
Forecast source: National Weather Service (api.weather.gov) for St. Clair (44.084, -93.861). Updated through the day.
Growing snapshot for St. Clair
Last spring frost
Apr 30
First fall frost
Oct 9
Growing season
161 days
Hardiness zone
5a
More local growing data for St. Clair: nearby ZIP 56080 weather · frost dates · planting calendar · Minnesota frost dates
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Climate data from the nearest NOAA station, Mankato, Mn (9.5 mi from St. Clair). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.