Lake St. Louis, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Lake St. Louis, a city in St. Charles County, Missouri.
Today
89°F
Sunny
Sunny, with a high near 89. South wind around 5 mph.
7-day forecast for Lake St. Louis
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 89°F | Sunny | 5 mph S | 0% |
| Tonight | 69°F | Mostly Clear | 5 mph S | 0% |
| Wednesday | 91°F | Mostly Sunny then Isolated Showers And Thunderstorms | 5 mph S | 19% |
| Wednesday Night | 71°F | Chance Showers And Thunderstorms | 5 mph S | 71% |
| Thursday | 87°F | Showers And Thunderstorms Likely | 3 mph S | 71% |
| Thursday Night | 69°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 2 mph SE | 19% |
| Friday | 88°F | Slight Chance Showers And Thunderstorms then Partly Sunny | 2 mph SW | 19% |
| Friday Night | 70°F | Chance Showers And Thunderstorms | 2 mph S | 29% |
| Saturday | 90°F | Chance Showers And Thunderstorms then Mostly Sunny | 3 mph SW | 29% |
| Saturday Night | 72°F | Mostly Clear | 5 mph S | 5% |
| Sunday | 93°F | Sunny | 7 mph SW | 3% |
| Sunday Night | 74°F | Mostly Clear | 7 mph S | 4% |
| Monday | 94°F | Sunny | 7 mph SW | 4% |
| Monday Night | 75°F | Slight Chance Showers And Thunderstorms | 3 to 7 mph SW | 15% |
Forecast source: National Weather Service (api.weather.gov) for Lake St. Louis (38.780, -90.786). Updated through the day.
Growing snapshot for Lake St. Louis
Last spring frost
Apr 10
First fall frost
Oct 26
Growing season
199 days
Hardiness zone
6b
More local growing data for Lake St. Louis: nearby ZIP 63367 weather · frost dates · planting calendar · Missouri frost dates
Nearby towns & communities
Augusta
Cottleville
Dardenne Prairie
Defiance
Flint Hill
Foristell
Josephville
New Melle
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 (8 mi from Lake St. Louis). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.