Connecticut has a generally temperate climate, with mild winters and warm summers. The January mean temperature is 27°F (–3°C) and the July mean is 70°F (21°C). Coastal areas have warmer winters and cooler summers than the interior. Norfolk, in the northwest, has a January mean temperature of 22°F (–6°C) and a July mean of 66°F (19°C), while Bridgeport, on the shore, has a mean of 30°F (–1°C) in January and of 71°F (22°C) in July. The highest recorded temperature in Connecticut was 106°F (41°C) in Danbury on 15 July 1995; the lowest, –32°F (–36°C) in Falls Village on 16 February 1943. The annual rainfall (1971–2000) was 46.2 in (117 cm), evenly distributed throughout the year. The state receives some 25 to 60 in (64 to 150 cm) of snow each year, with heaviest snowfall in the northwest.

Weather annals reveal a remarkable range and variety of climatic phenomena. Severe droughts were experienced in 1749, 1762, 1929–33, the early 1940s, 1948–50, and 1956–57. The worst recent drought, which occurred in 1963–66, resulted in a severe forest-fire hazard, damage to crops, and rationing of water. Downtown Hartford was inundated by a flood in March 1936. On 21 September 1938, a hurricane struck west of New Haven and followed the Connecticut Valley northward, causing 85 deaths and property losses of more than $125 million. Severe flooding occurred in 1955 and again in 1982. In the latter year, property damage exceeded $266 million.