St. Clair, MO Weather & Growing Conditions
This Afternoon
73°F
Light Rain Likely
Rain likely and a slight chance of thunderstorms. Cloudy. High near 73, with temperatures falling to around 65 in the afternoon. South wind around 13 mph, with gusts as high as 26 mph. Chance of precipitation is 60%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 73°F | Light Rain Likely | 13 mph S | 62% |
| Tonight | 49°F | Light Rain Likely | 5 to 12 mph SW | 68% |
| Wednesday | 61°F | Mostly Cloudy | 3 to 8 mph W | 3% |
| Wednesday Night | 38°F | Partly Cloudy | 3 mph SW | 0% |
| Thursday | 65°F | Sunny | 6 mph W | 4% |
| Thursday Night | 38°F | Mostly Cloudy | 2 mph NW | 13% |
| Friday | 56°F | Partly Sunny | 5 mph NW | 4% |
| Friday Night | 34°F | Mostly Cloudy | 1 mph N | 3% |
| Saturday | 56°F | Partly Sunny | 1 mph NW | 0% |
| Saturday Night | 31°F | Partly Cloudy | 0 mph | 2% |
| Sunday | 62°F | Sunny | 0 to 3 mph W | 7% |
| Sunday Night | 31°F | Mostly Clear | 1 mph NW | 3% |
| Monday | 66°F | Sunny | 3 mph W | 2% |
| Monday Night | 36°F | Mostly Clear | 2 mph W | 1% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for St. Clair, MO
Last spring frost
Apr 11
First fall frost
Oct 23
Growing season
194 days
Hardiness zone
6b
Explore more for St. Clair, MO: full frost dates · planting calendar · Missouri frost dates
Climate data from the nearest NOAA station, Union, Mo (8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.