Climate Insights for Dorchester

The climate in Dorchester is cool. The average annual temperature is 9°C and approximately 1004mm of precipitation falls per year. Dorchester receives a notable amount of rainfall throughout the year, including during its driest month. Dorchester is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are February, January, March, when temperatures can drop to -7°C. Snowfall occurs from January to December, with around 98cm accumulating over the season.

Temperatures in Dorchester vary considerably across the year, with a 34°C difference between the coldest and warmest months. The warmest month is July, when average highs reach 27°C and the mean temperature sits around 22°C. The coldest month is February, when overnight lows fall to -7°C and the daily average is -4°C. On average, daily temperatures fluctuate by about 9°C between overnight lows and afternoon highs. The sharpest temperature change occurs between April and May, with a 7°C shift in average temperatures.

Dorchester is a moderately rainy area, receiving approximately 1004mm of precipitation annually, which averages out to around 84mm per month. The wettest month is April, averaging 106mm of rainfall. June and August also tend to see above-average precipitation. The driest month is September, with just 64mm. That's 42mm less than April, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around. Snowfall is a regular feature from January to December, with around 98cm accumulating over the season. February typically sees the most snow at around 25cm.

Dorchester 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 February, averaging 22km/h, noticeable enough to affect lighter outdoor activities. The calmest conditions occur in August, 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 be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 21km/h in winter, 20km/h in spring, 17km/h in summer, 19km/h in autumn.

It is currently spring in Dorchester, which began on March 20, 2026. Dorchester is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 27°C, while the coldest stretch bottoms out in February near -7°C. Summer is next, beginning on June 21, 2026 — 89 days from now.

The best time to visit Dorchester is during July, August and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 20°C with modest rainfall averaging 84mm per month. By contrast, February can be quite cold with temperatures dropping to -7°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Dorchester 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. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. 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.