Climate Insights for Thornhill

The climate in Thornhill is temperate. The average annual temperature is 18°C and approximately 464mm of precipitation falls per year. März is the wettest month, receiving around 53mm of rainfall. Thornhill is in the Southern Hemisphere. The seasons are reversed — summer runs from December to February, while winter falls between June and August. The summer months are: Januar, Februar, März. The coldest months are Juli, August, Juni, when temperatures can drop to 8°C.

Thornhill sees moderate temperature variation throughout the year, ranging from 8°C to 28°C. The warmest month is Januar, when average highs reach 28°C and the mean temperature sits around 22°C. Juli is the coolest month, with minimum temperatures around 8°C and an average of 13°C. On average, daily temperatures fluctuate by about 12°C between overnight lows and afternoon highs. The sharpest temperature change occurs between March and April, with a 3°C shift in average temperatures.

Thornhill is a relatively dry area, receiving approximately 464mm of precipitation annually, which averages out to around 39mm per month. The wettest month is March, averaging 53mm of rainfall. February and April also tend to see above-average precipitation. The driest month is August, with just 25mm. That's 28mm less than March, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around.

Thornhill is mildly breezy, with an average annual wind speed of 19km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is December, averaging 22km/h, noticeable enough to affect lighter outdoor activities. The calmest conditions occur in May, with average winds dropping to 16km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 6km/h between the calmest and windiest months. Wind tends to pick up during the summer months. The seasonal averages are 18km/h in winter, 21km/h in spring, 21km/h in summer, 17km/h in autumn.

It is currently winter in Thornhill, which began on June 21, 2026. Thornhill is in the Southern Hemisphere, where the seasons are reversed — spring starts in September, summer in December, autumn in March, and winter in June. The warmest period peaks in Januar at around 28°C, while the coldest stretch bottoms out in Juli near 8°C. Autumn is next, beginning on March 20, 2026 — 2 days from now.

The best time to visit Thornhill is during Januar, Februar, März, April, Mai, September, Oktober, November and Dezember, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 42mm per month. By contrast, Juli can be quite cold with temperatures dropping to 8°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Thornhill based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.