St. Clair, MO Weather & Growing Conditions
Today
90°F
Patchy Fog then Sunny
Patchy fog before 8am. Sunny, with a high near 90. South wind around 2 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 90°F | Patchy Fog then Sunny | 2 mph S | 0% |
| Tonight | 67°F | Mostly Clear | 2 mph S | 0% |
| Wednesday | 91°F | Sunny | 3 mph S | 10% |
| Wednesday Night | 70°F | Slight Chance Showers And Thunderstorms | 2 mph S | 62% |
| Thursday | 88°F | Showers And Thunderstorms Likely | 2 mph S | 69% |
| Thursday Night | 68°F | Mostly Cloudy then Chance Showers And Thunderstorms | 1 mph S | 34% |
| Friday | 88°F | Chance Showers And Thunderstorms | 2 mph SW | 34% |
| Friday Night | 68°F | Chance Showers And Thunderstorms | 1 mph SW | 27% |
| Saturday | 90°F | Chance Showers And Thunderstorms | 2 mph SW | 27% |
| Saturday Night | 71°F | Mostly Clear | 3 mph S | 9% |
| Sunday | 92°F | Sunny | 5 mph SW | 4% |
| Sunday Night | 72°F | Mostly Clear | 3 mph S | 5% |
| Monday | 94°F | Sunny | 5 mph SW | 5% |
| Monday Night | 74°F | Mostly Clear | 5 mph S | 8% |
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 Aug 4, 2026.