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Thornhill (ON) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Thornhill.
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Climate overview of Thornhill
Thornhill, Ontario, Canada, experiences significant temperature variation throughout the year. Summers bring daytime highs of 27°C (81°F) in July, while winters cool to 0°C (32°F) in January.
Thornhill sees a moderate amount of rain/snowfall, totalling around 911 mm (36 in) per year. It experiences warm summers and very cold winters, creating some seasonal variation. Sunshine peaks in July, when the city sees around 9.3 hours of sunshine per day.
Thornhill Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Thornhill - and find the best time to visit.
Monthly Temperature in Thornhill
Depending on the time of the year, temperatures range from comfortable to very cold in Thornhill. Average maximum daytime temperatures range from a comfortable 27°C (81°F) in July, the warmest time of the year, to a very cold 0°C (32°F) during cooler months like January.
At night, you can expect temperatures ranging from 17°C (63°F) in July to around -9°C (16°F) during January.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Thornhill
Generally, Thornhill has a moderate amount of precipitation, averaging 911 mm (36 in) of rain/snowfall annually. Year-round, Thornhill has a balanced climate with minimal variation in precipitation. The difference between the wettest month, April, with 87 mm (3.4 in), and the driest month, February, with 62 mm (2.4 in), is minimal. For more details, please visit our Thornhill Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Thornhill
Seasonal changes in sunshine hours are quite dramatic in Thornhill. While July receives considerable daily sunshine with up to 9.3 hours, December marks the darkest time of the year, where sunshine is scarce with only 2.6 hours of sunlight per day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Data from: Toronto, Canada (16 KM, 10 Miles).
Daily hours of sunshine
Data from: Toronto, Canada (16 KM, 10 Miles).
Daily percentage of sunshine
Data from: Toronto, Canada (16 KM, 10 Miles).
Humidity in Thornhill by Month
The city experiences its highest humidity in September, reaching 87%. In April, the humidity drops to its lowest level at 76%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Data from: Toronto, Canada (16 KM, 10 Miles).
Best Time to Visit Thornhill
For comfortable weather, consider visiting Thornhill in June, July, August and September. Conditions are usually least favourable in January, February, March, 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
cold
Feb
cold
Mar
cold
Apr
mixed
May
very good
Jun
excellent
Jul
excellent
Aug
excellent
Sep
excellent
Oct
good
Nov
cold
Dec
cold
- Best overall: June, July, August and September
- Warmest weather: July and August
- Most sunshine: July
- Seasonal pattern: Warm summers and very cold winters
- Coldest conditions: January, with freezing nights around -9°C (16°F).
Frequently asked questions about the climate in Thornhill
What is the best time to visit Thornhill?
June, July, August and September typically offer the most optimal weather in Thornhill. In contrast, January, February, March, November and December tend to have less optimal conditions. Thornhill has warm summers and very cold winters.
What temperatures can I expect in Thornhill?
Daytime highs range from 0°C (32°F) in January to 27°C (81°F) in July. Nighttime lows range from -9°C (16°F) to 17°C (63°F). Temperatures vary considerably through the year.
How much rain does Thornhill get?
Annual rainfall is around 911 mm (36 in). April is the wettest month with 87 mm (3.4 in), while February is the driest with 62 mm (2.4 in).
How sunny is Thornhill?
Thornhill receives around 2,070 hours of sunshine per year. July is the sunniest month with 280 hours, while December is the cloudiest with just 78 hours. Overall, Thornhill enjoys abundant sunshine.
Thornhill 3-Day Forecast
Thornhill on the map
Thornhill is highlighted - select any city to see its climate.
Popular in September
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