Under the Köppen climate classification, using the 0 °C (32 °F) isotherm, New York City features a humid subtropical climate (Cfa), and is thus the northernmost major city on the North American continent with this categorization. The suburbs to the immediate north and west lie in the transitional zone between humid subtropical and humid continental climates (Dfa).[211][212] For the Trewartha classification, it is defined as humid continental (Dc), which is compatible in ecological terms, more similar to Eastern Europe.[213][214] Annually, the city averages 234 days with at least some sunshine.[215] The city lies in the USDA 7b plant hardiness zone.[216]

Winters are cold and damp. The daily mean temperature in January, the area's coldest month, is 32.6 °F (0.3 °C);[217]temperatures usually drop to 10 °F (−12 °C) several times per winter,[218] and reach 60 °F (16 °C) several days in the coldest winter month. Spring and autumn are unpredictable and can range from chilly to warm, although they are usually mild with low humidity. Summers are typically warm to hot and humid, with a daily mean temperature of 76.5 °F (24.7 °C) in July.[217] Nighttime conditions are often exacerbated by the urban heat island phenomenon, while daytime temperatures exceed 90 °F (32 °C) on average of 17 days each summer and in some years exceed 100 °F (38 °C), although the last time this happened was July 23, 2011.[219] Extreme temperatures have ranged from −15 °F (−26 °C), recorded on February 9, 1934, up to 106 °F (41 °C) on July 9, 1936.[217] The record cold daily maximum was 2 °F (−17 °C) on December 30, 1917, while, conversely, the record warm daily minimum was 84 °F (29 °C), last recorded on July 22, 2011.[219] The average water temperature of the nearby Atlantic Ocean ranges from 39.7 °F (4.3 °C) in February to 74.1 °F (23.4 °C) in August.[220]