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Saint Marys (ON) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Saint Marys.
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Climate overview of Saint Marys
Saint Marys, Ontario, Canada, sees big temperature differences between seasons, with July peaking at 27°C (81°F) and January dropping to -1°C (30°F).
The city receives considerable rain/snowfall, with around 1088 mm (43 in) annually. June is the wettest month. It has warm summers and very cold winters.
Saint Marys Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Saint Marys - and find the best time to visit.
Monthly Temperature in Saint Marys
Visitors to Saint Marys can expect significant temperature changes throughout the year. Typically, average maximum daytime temperatures range from a comfortable 27°C (81°F) in July to a very cold -1°C (30°F) in the coolest month, January.
Nights vary from 15°C (59°F) in July to around -10°C (14°F) during the colder months.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Saint Marys
Saint Marys is known for its substantial rain/snowfall, with annual precipitation reaching 1088 mm (43 in). Precipitation levels in Saint Marys remain relatively steady throughout the year. June has the most rain, with 109 mm (4.3 in) over 11 days. In the driest month March, this drops slightly to 73 mm (2.9 in), making the city's climate fairly predictable. For more details, please visit our Saint Marys Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Best Time to Visit Saint Marys
For comfortable weather, consider visiting Saint Marys in August and September. Conditions are usually least favourable in January, February, March, April, November and December.
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
Jan
very cold
Feb
cold
Mar
cold
Apr
wet
May
very good
Jun
very good
Jul
very good
Aug
excellent
Sep
excellent
Oct
good
Nov
cold
Dec
cold
- Best overall: August and September
- Warmest weather: July and August
- Fewer rainy days: May, June, July, August and September
- Seasonal pattern: Warm summers and very cold winters
- Coldest conditions: January, with freezing nights around -10°C (14°F).
Frequently asked questions about the climate in Saint Marys
What is the best time to visit Saint Marys?
August and September typically offer the most optimal weather in Saint Marys. In contrast, January, February, March, April, November and December tend to have less optimal conditions. Saint Marys has warm summers and very cold winters.
What temperatures can I expect in Saint Marys?
Daytime highs range from -1°C (30°F) in January to 27°C (81°F) in July. Nighttime lows range from -10°C (14°F) to 15°C (59°F). Temperatures vary considerably through the year.
How much rain does Saint Marys get?
Annual rainfall is around 1088 mm (43 in). June is the wettest month with 109 mm (4.3 in), while March is the driest with 73 mm (2.9 in).
Saint Marys 3-Day Forecast
Saint Marys on the map
Saint Marys is highlighted - select any city to see its climate.
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