Winchester, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Winchester, a city in St. Louis County, Missouri.
This Afternoon
99°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Sunny, with a high near 99. Heat index values as high as 104. South wind around 2 mph. Chance of precipitation is 30%.
7-day forecast for Winchester
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 99°F | Chance Showers And Thunderstorms | 2 mph S | 26% |
| Tonight | 74°F | Slight Chance Showers And Thunderstorms then Mostly Clear | 2 mph SE | 23% |
| Saturday | 98°F | Mostly Sunny | 3 to 7 mph SW | 5% |
| Saturday Night | 74°F | Partly Cloudy | 3 mph S | 2% |
| Sunday | 93°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 6 mph W | 20% |
| Sunday Night | 68°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 6 mph N | 62% |
| Monday | 80°F | Showers And Thunderstorms Likely | 7 mph N | 71% |
| Monday Night | 61°F | Showers And Thunderstorms Likely then Slight Chance Showers And Thunderstorms | 5 to 8 mph N | 71% |
| Tuesday | 71°F | Slight Chance Rain Showers then Mostly Cloudy | 8 mph N | 21% |
| Tuesday Night | 55°F | Mostly Cloudy | 3 to 7 mph N | 6% |
| Wednesday | 74°F | Mostly Sunny | 6 mph N | 1% |
| Wednesday Night | 56°F | Partly Cloudy | 5 mph N | 1% |
| Thursday | 75°F | Mostly Sunny | 2 to 6 mph N | 3% |
| Thursday Night | 59°F | Partly Cloudy | 5 mph NE | 3% |
Forecast source: National Weather Service (api.weather.gov) for Winchester (38.590, -90.526). Updated through the day.
Growing snapshot for Winchester
Last spring frost
Apr 4
First fall frost
Oct 29
Growing season
206 days
Hardiness zone
7a
More local growing data for Winchester: nearby ZIP 63021 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 7 Ssw, Mo (8.1 mi from Winchester). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.