St. Peters, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Peters, a city in St. Charles County, Missouri.
Today
97°F
Partly Sunny
Partly sunny, with a high near 97. Heat index values as high as 100. Southwest wind around 7 mph.
7-day forecast for St. Peters
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 97°F | Partly Sunny | 7 mph SW | 3% |
| Tonight | 73°F | Partly Cloudy | 5 mph SW | 4% |
| Sunday | 91°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 2 to 6 mph W | 41% |
| Sunday Night | 67°F | Showers And Thunderstorms Likely | 7 mph N | 70% |
| Monday | 77°F | Showers And Thunderstorms Likely | 6 to 9 mph NE | 70% |
| Monday Night | 59°F | Chance Showers And Thunderstorms | 6 to 9 mph NE | 31% |
| Tuesday | 70°F | Slight Chance Rain Showers then Mostly Cloudy | 10 mph N | 20% |
| Tuesday Night | 54°F | Mostly Cloudy | 5 to 9 mph N | 3% |
| Wednesday | 73°F | Mostly Sunny | 8 mph N | 1% |
| Wednesday Night | 56°F | Partly Cloudy | 2 to 7 mph NE | 0% |
| Thursday | 76°F | Mostly Sunny | 6 mph N | 2% |
| Thursday Night | 58°F | Partly Cloudy | 5 mph NE | 4% |
| Friday | 77°F | Partly Sunny | 6 mph NE | 8% |
| Friday Night | 58°F | Partly Cloudy | 5 mph NE | 6% |
Forecast source: National Weather Service (api.weather.gov) for St. Peters (38.782, -90.604). Updated through the day.
Growing snapshot for St. Peters
Last spring frost
Apr 9
First fall frost
Oct 26
Growing season
198 days
Hardiness zone
6b
More local growing data for St. Peters: nearby ZIP 63376 weather · frost dates · planting calendar · Missouri frost dates
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Climate data from the nearest NOAA station, St Peters 2 Se, Mo (2.6 mi from St. Peters). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.