Climate of New England
The climate of New England varies greatly across its 500-mile (800 km) span from northern Maine to southern Connecticut:
Interior Maine, New Hampshire, Vermont, and western Massachusetts have a humid continental climate (Dfb in Köppen climate classification). In this region the winters are long, cold, and heavy snow is common (most locations receive 60 to 120 inches (1,500 to 3,000 mm) of snow annually in this region). The summer's months are moderately warm, though summer is rather short and rainfall is spread through the year. Cities like Worcester, Massachusetts, Concord, New Hampshire, and Burlington, Vermont, average 60 to 80 inches (1,500 to 2,000 mm) of snow annually. The frost-free growing season ranges from 90 days in far northern Maine and the mountains of New Hampshire and Vermont to 140 days along the Maine coast and in most of western Massachusetts.
In central and eastern Massachusetts, Rhode Island, and most of Connecticut, the same humid continental prevails (Dfa), though summers are warm to hot, winters are shorter, and there is less snowfall (especially in the coastal areas where it is often warmer), with the general exception of the higher elevations and other normally cooler locations. Cities like Boston, Hartford, and Providence receive 35 to 45 inches (890 to 1,140 mm) of snow annually. Summers can occasionally be hot and humid, with high temperatures in the lower Connecticut Valley of Massachusetts and northern Connecticut between 90 and 100 °F (32 and 38 °C). Summer thunderstorms are common between June and August. The frost-free growing season ranges from 140 days in parts of central Massachusetts to near 160 days across interior Connecticut and most Rhode Island.
Southern and coastal Connecticut is the broad transition zone from continental climates to subtropical climates to the south. The coast of Connecticut from Stamford, through the Bridgeport/New Haven area to New London is the mildest area of New England. Summers are frequently hot and humid, and winters are cool with a mix of snow and rain. Most cities along the Connecticut coast average 20 to 25 inches (510 to 640 mm) of snow annually, though in some winters there is little snowfall. Winters also tend to be sunnier in southern Connecticut and southern Rhode Island compared to northern and central New England. Summers can be hot and humid, and thunderstorms are common from June through September. Tropical cyclones have struck southern Connecticut and coastal Rhode Island several times, including in 1938 and 1954 (Hurricane Carol) when several hundred people were killed. The frost-free growing season approaches 200 days along the Connecticut coast.