Williamstown Weather & Climate: Best Time to Visit

In Williamstown, temperatures differ significantly between summer and winter months. Average maximum daytime temperatures range from a comfortable 29°C (84°F) in January, the warmest time of the year, to a moderate 15°C (59°F) during cooler months like August.

At night, you can expect temperatures ranging from 15°C (59°F) in January to around 6°C (43°F) during August.

Check out our detailed temperature page for more information.

Temperature ranges by month

Williamstown's climate is marked by below-average rainfall, accumulating 472 mm (19 in) of precipitation yearly. Significant seasonal changes in precipitation occur throughout the year. In the wettest month, September it receives moderate rainfall, averaging 59 mm (2.3 in) of precipitation, recorded across 9 rainy days. In contrast, the driest month March brings less rainfall, with 18 mm (0.7 in) over 6 rainy days. For more details, please visit our Williamstown Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

Seasonal changes in sunshine hours are quite dramatic in Williamstown. While January receives considerable daily sunshine with up to 10.9 hours, June marks the darkest time of the year, where sunshine is scarce with only 4.7 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

The relative humidity is moderate throughout the year in Williamstown.

The city experiences its highest humidity in June, reaching 61%. In January, the humidity drops to its lowest level at 36%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year