St. Clair, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Clair, a city in Franklin County, Missouri.
Tonight
50°F
Mostly Cloudy then Slight Chance Light Rain
A slight chance of rain between midnight and 1am, then a slight chance of drizzle between 1am and 5am. Mostly cloudy, with a low around 50. Southwest wind around 9 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.
7-day forecast for St. Clair
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 50°F | Mostly Cloudy then Slight Chance Light Rain | 9 mph SW | 16% |
| Wednesday | 61°F | Mostly Cloudy | 5 to 10 mph W | 3% |
| Wednesday Night | 39°F | Mostly Clear | 3 mph W | 0% |
| Thursday | 63°F | Sunny | 3 to 7 mph W | 3% |
| Thursday Night | 38°F | Mostly Cloudy | 3 mph NW | 13% |
| Friday | 56°F | Mostly Cloudy | 6 mph NW | 4% |
| Friday Night | 34°F | Mostly Cloudy | 2 mph N | 3% |
| Saturday | 55°F | Partly Sunny | 1 mph NW | 0% |
| Saturday Night | 31°F | Partly Cloudy | 1 mph NW | 2% |
| Sunday | 61°F | Sunny | 3 mph W | 7% |
| Sunday Night | 32°F | Mostly Clear | 2 mph NW | 3% |
| Monday | 66°F | Sunny | 3 mph W | 2% |
| Monday Night | 36°F | Mostly Clear | 2 mph W | 1% |
| Tuesday | 68°F | Sunny | 2 mph W | 1% |
Forecast source: National Weather Service (api.weather.gov) for St. Clair (38.347, -90.994). Updated through the day.
Growing snapshot for St. Clair
Last spring frost
Apr 11
First fall frost
Oct 23
Growing season
194 days
Hardiness zone
6b
More local growing data for St. Clair: nearby ZIP 63077 weather · frost dates · planting calendar · Missouri frost dates
Nearby towns & communities
Berger
Charmwood
Gerald
Gray Summit
LaBarque Creek
Lake St. Clair
Lake Tekakwitha
Leslie
Miramiguoa Park
New Haven
Oak Grove Village
Pacific
Parkway
Stanton
Sullivan
Three Creeks
Union
Villa Ridge
Washington
Climate data from the nearest NOAA station, Union, Mo (8 mi from St. Clair). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.