New York: Annual Weather Averages. July is the hottest month in New York with an average temperature of 25°C (76°F) and the coldest is January at 2°C (35°F) with the most daily sunshine hours at 11 in July.The wettest month is May with an average of 114mm of rain.ew York: Annual Weather Averages. July is the hottest month in New York with an average temperature of 25°C (76°F) and the coldest is January at 2°C (35°F) with the most daily sunshine hours at 11 in July.