Defiance, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Defiance, a community in St. Charles County, Missouri.
This Afternoon
58°F
Cloudy
Cloudy, with a high near 58. West wind around 7 mph.
7-day forecast for Defiance
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 58°F | Cloudy | 7 mph W | 0% |
| Tonight | 42°F | Partly Cloudy | 5 mph SW | 0% |
| Thursday | 62°F | Mostly Sunny | 5 to 9 mph W | 9% |
| Thursday Night | 43°F | Isolated Rain Showers then Mostly Cloudy | 3 mph NW | 16% |
| Friday | 55°F | Partly Sunny | 5 to 8 mph N | 4% |
| Friday Night | 30°F | Mostly Clear | 0 to 3 mph N | 0% |
| Saturday | 54°F | Mostly Sunny | 1 mph N | 0% |
| Saturday Night | 30°F | Mostly Clear | 0 mph | 0% |
| Sunday | 61°F | Sunny | 2 mph W | 0% |
| Sunday Night | 33°F | Clear | 0 mph | 0% |
| Monday | 66°F | Sunny | 0 to 3 mph SW | 0% |
| Monday Night | 37°F | Clear | 2 mph W | 1% |
| Tuesday | 67°F | Sunny | 2 mph W | 3% |
| Tuesday Night | 39°F | Mostly Clear | 0 mph | 3% |
Forecast source: National Weather Service (api.weather.gov) for Defiance (38.633, -90.785). Updated through the day.
Growing snapshot for Defiance
Last spring frost
Apr 10
First fall frost
Oct 26
Growing season
199 days
Hardiness zone
6b
More local growing data for Defiance: nearby ZIP 63341 weather · frost dates · planting calendar · Missouri frost dates
Nearby towns & communities
Augusta
Cottleville
Dardenne Prairie
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O'Fallon
St. Paul
St. Peters
Weldon Spring
Weldon Spring Heights
Wentzville
West Alton
Climate data from the nearest NOAA station, Weldon Spring Nws, Mo (7.2 mi from Defiance). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 5, 2026.