St. Charles, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Charles, a city in St. Louis County, Missouri.
Today
97°F
Partly Sunny
Partly sunny, with a high near 97. Heat index values as high as 100. Southwest wind 5 to 8 mph.
7-day forecast for St. Charles
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 97°F | Partly Sunny | 5 to 8 mph SW | 1% |
| Tonight | 73°F | Partly Cloudy | 2 to 6 mph SW | 4% |
| Sunday | 91°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 3 to 7 mph W | 40% |
| Sunday Night | 67°F | Showers And Thunderstorms Likely | 6 to 9 mph NE | 70% |
| Monday | 77°F | Showers And Thunderstorms Likely | 7 to 10 mph NE | 70% |
| Monday Night | 59°F | Chance Showers And Thunderstorms | 7 to 10 mph NE | 33% |
| Tuesday | 70°F | Slight Chance Rain Showers then Partly Sunny | 12 mph NE | 20% |
| Tuesday Night | 55°F | Mostly Cloudy | 6 to 10 mph N | 4% |
| Wednesday | 73°F | Mostly Sunny | 9 mph N | 1% |
| Wednesday Night | 56°F | Partly Cloudy | 3 to 8 mph NE | 0% |
| Thursday | 75°F | Mostly Sunny | 3 to 7 mph N | 2% |
| Thursday Night | 58°F | Partly Cloudy | 2 to 6 mph NE | 3% |
| Friday | 77°F | Partly Sunny | 3 to 7 mph NE | 7% |
| Friday Night | 59°F | Partly Cloudy | 6 mph NE | 6% |
Forecast source: National Weather Service (api.weather.gov) for St. Charles (38.796, -90.515). Updated through the day.
Growing snapshot for St. Charles
Last spring frost
Apr 8
First fall frost
Oct 29
Growing season
203 days
Hardiness zone
6b
More local growing data for St. Charles: nearby ZIP 63045 weather · frost dates · planting calendar · Missouri frost dates
Nearby towns & communities
Affton
Ballwin
Bel-Nor
Bel-Ridge
Bella Villa
Bellefontaine Neighbors
Bellerive Acres
Berkeley
Beverly Hills
Black Jack
Breckenridge Hills
Brentwood
Bridgeton
Calverton Park
Castle Point
Champ
Charlack
Chesterfield
Clarkson Valley
Clayton
Concord
Cool Valley
Country Club Hills
Country Life Acres
Crestwood
Creve Coeur
Crystal Lake Park
Dellwood
Des Peres
Edmundson
Climate data from the nearest NOAA station, St Charles Elm Pt, Mo (4.1 mi from St. Charles). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.