Although Massachusetts is a relatively small state, there are significant climatic differences between its eastern and western sections. The entire state has cold winters and moderately warm summers, but the Berkshires in the west have both the coldest winters and the coolest summers. The normal January temperature in Pittsfield in the Berkshires is 22°F (–6°C), while the normal July temperature is 68°F (20°C). The interior lowlands are several degrees warmer in both winter and summer; the normal July temperature is 71°F (22°C). The coastal sections are the warmest areas of the state; the normal January temperature for Boston is 30°F (–1°C), and the normal July temperature is 74°F (23°C). The record high temperature in the state is 107°F (42°C), established at Chester and New Bedford on 2 August 1975; the record low is –35°F (–37°C), registered at Chester on 12 January 1981.

Precipitation ranges from 39 to 46 in (99 to 117 cm) annually, with an average for Boston (1971–2000) of 42.5 in (108 cm). The average snowfall for Boston is 42 in (107 cm), with the range in the Berkshires considerably higher. Boston's average wind speed is 13 mph (21 km/hr).