St. Marys, KS Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Marys, a city in Pottawatomie County, Kansas.
Today
96°F
Slight Chance Showers And Thunderstorms
A slight chance of showers and thunderstorms. Mostly sunny, with a high near 96. Southwest wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.
7-day forecast for St. Marys
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 96°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 16% |
| Tonight | 66°F | Chance Showers And Thunderstorms | 5 mph N | 80% |
| Sunday | 77°F | Chance Showers And Thunderstorms | 5 to 10 mph N | 46% |
| Sunday Night | 62°F | Chance Showers And Thunderstorms | 5 to 10 mph N | 40% |
| Monday | 69°F | Chance Rain Showers | 5 to 10 mph N | 28% |
| Monday Night | 54°F | Mostly Cloudy | 5 to 10 mph NE | 5% |
| Tuesday | 66°F | Partly Sunny | 5 mph NE | 1% |
| Tuesday Night | 50°F | Partly Cloudy | 5 mph E | 1% |
| Wednesday | 69°F | Mostly Sunny | 0 to 5 mph E | 2% |
| Wednesday Night | 54°F | Partly Cloudy | 0 to 5 mph E | 13% |
| Thursday | 72°F | Chance Rain Showers | 0 to 5 mph E | 33% |
| Thursday Night | 59°F | Slight Chance Showers And Thunderstorms | 5 mph E | 25% |
| Friday | 73°F | Chance Showers And Thunderstorms | 5 mph E | 28% |
| Friday Night | 60°F | Mostly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph E | 21% |
Forecast source: National Weather Service (api.weather.gov) for St. Marys (39.194, -96.064). Updated through the day.
Growing snapshot for St. Marys
Last spring frost
Apr 18
First fall frost
Oct 19
Growing season
183 days
Hardiness zone
6b
More local growing data for St. Marys: nearby ZIP 66536 weather · frost dates · planting calendar · Kansas frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Wamego 4 W, Ks (16.1 mi from St. Marys). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.