St. Marys, OH Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Marys, a city in Auglaize County, Ohio.
Overnight
62°F
Light Rain Likely
Rain likely. Cloudy, with a low around 62. South wind around 16 mph, with gusts as high as 30 mph. Chance of precipitation is 70%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for St. Marys
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 62°F | Light Rain Likely | 16 mph S | 67% |
| Wednesday | 67°F | Light Rain | 13 to 20 mph S | 99% |
| Wednesday Night | 49°F | Chance Light Rain then Mostly Cloudy | 7 to 10 mph SW | 29% |
| Thursday | 61°F | Partly Sunny | 8 to 16 mph SW | 1% |
| Thursday Night | 45°F | Slight Chance Light Rain | 3 to 8 mph SW | 15% |
| Friday | 55°F | Chance Light Rain | 3 to 12 mph W | 46% |
| Friday Night | 36°F | Chance Light Rain then Mostly Cloudy | 6 to 10 mph NW | 46% |
| Saturday | 53°F | Partly Sunny | 6 to 9 mph NW | 3% |
| Saturday Night | 33°F | Partly Cloudy | 5 mph W | 3% |
| Sunday | 56°F | Mostly Sunny | 2 to 12 mph W | 3% |
| Sunday Night | 33°F | Mostly Clear | 3 to 8 mph W | 4% |
| Monday | 59°F | Sunny | 3 to 9 mph SW | 3% |
| Monday Night | 38°F | Mostly Clear | 6 mph SW | 1% |
| Tuesday | 63°F | Sunny | 6 to 9 mph W | 1% |
Forecast source: National Weather Service (api.weather.gov) for St. Marys (40.548, -84.392). Updated through the day.
Growing snapshot for St. Marys
Last spring frost
Apr 27
First fall frost
Oct 19
Growing season
175 days
Hardiness zone
6a
More local growing data for St. Marys: nearby ZIP 45885 weather · frost dates · planting calendar · Ohio frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Celina 3 Ne, Oh (7.7 mi from St. Marys). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.