Thornhill (ON) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Thornhill.
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. 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
Daily hours of sunshine
Daily percentage of sunshine
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
Best Time to Visit Thornhill
Rainfall during this time ranges from 73 mm (2.9 in) in August to 86 mm (3.4 in) in June. This means you can expect a mix of sunny days and occasional showers. Need help choosing your next travel destination? We offer a specialized tool that matches you with locations based on your weather preferences. Explore destinations that suit your climate preferences.
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.
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) 3-Day Forecast
Thornhill on the map
Thornhill is highlighted — select any city to see its climate.
Popular this month
Where to go in July — average daytime high across popular destinations.
Niagara Falls
27°C (81°F) Montréal28°C (82°F) Ottawa27°C (81°F) Quebec City
26°C (79°F) Toronto26°C (79°F) Calgary24°C (75°F) Vancouver22°C (72°F) Whistler
19°C (66°F) 
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