Although the New York City area is adjacent to the Atlantic Ocean, the climate is dominated by major airflows and weather patterns of continental origin. Atmospheric circulation patterns bring frequent and substantial amounts of precipitation to the region. Evaporation from the water adds considerable moisture to the air, and humidity is often high. The average rainfall is 47 inches; the average snowfall is 29 inches.

The Atlantic Ocean and the waters of the New York harbor have a secondary effect on the climate. Temperatures are moderated, especially in winter, by the nearby large areas of water, extending the growing season and the number of frost-free days. The average date of the last spring freeze (32o F) is April 10, and the average date of the first fall freeze (32o F) is November 4, for an average freeze-free growing season of 207 days. Winters are short and moderately cold. The average low temperatures are below freezing in December, January, and February. Summer weather is generally warm to hot, and the high humidity makes conditions uncomfortable. The average high temperatures are above 80o F in June, July, and August.