Climate
Philadelphia's climate falls in the humid subtropical climate zone, although it is the northernmost city in the United States that is considered to meet this classification. Because Philadelphia is on the far northern end of this climate zone, some of its outlying suburbs, especially to the north and west, are considered to fall in the humid continental zone. Summers are typically hot and muggy, fall and spring are generally mild, and winter is cold, although periods of extreme cold are infrequent. Snowfall is variable, with some winters bringing light snow and others bringing many significant snowstorms. It is common for the heavier snowfall to occur north and west of the city. The average annual snowfall is 21 in (534 mm). Precipitation is generally spread throughout the year, with eight to eleven wet days per month, at an average annual rate of 42 in (1068 mm).
January lows average 23°F (–5°C) and highs average 38°F (3°C). The lowest officially recorded temperature was –11°F (–24°C) on February 9, 1934, but temperatures below 14°F (–10°C) occur only a few times a year. July lows average 67°F (20°C) and highs average 86° F (30°C), although heat waves see highs above 95°F (35°C) with the heat index running as high as 110°F (43°C). The highest temperature on record was 106°F (41°C) on August 7, 1918. Early fall and late winter are generally driest, with February being the driest month with only 2.74 in (69.8 mm) of average precipitation.
(Source: Wikipedia.org)
