Philadelphia’s climate is characterized by four distinct seasons, each offering unique weather patterns and experiences. However, recent trends indicate notable shifts in these patterns, prompting a closer look at what residents can expect throughout the year.
Spring: A Gradual Warm-Up
Spring in Philadelphia spans from March through May, with temperatures rising from an average of 49.8°F (9.9°C) in March to 72°F (22.2°C) by May. Relative humidity during this period ranges between 72% and 75%, accompanied by moderate rainfall, making for a pleasant transition from winter to summer. Source
Summer: Heat and Humidity
Summers, from June to August, are typically warm and humid. July stands out as the hottest month, with average highs reaching 86.4°F (30.2°C). Humidity levels hover between 72% and 74%, and August often sees peak rainfall at 1.65 inches (42mm). Notably, the city has experienced an increase in days with temperatures exceeding 90°F, averaging 30 such days annually, up from 21 in the 1950s. Source Source
Autumn: Crisp and Colorful
Autumn, from September through November, brings cooler temperatures, ranging from 76.6°F (24.8°C) in September to 52.7°F (11.5°C) in November. The season is marked by moderate humidity and rainfall, providing ideal conditions for enjoying the vibrant fall foliage. Source
Winter: Milder Cold Spells
Winters, spanning December to February, are cold with average lows dipping to 25.5°F (-3.6°C) in January. Snowfall is common, with February typically recording the highest levels at 0.98 inches (25mm). However, analyses indicate that cold streaks have shortened by an average of 12 days since 1970, suggesting milder winters in recent decades. Source Source
Climate Change Impacts
Philadelphia is experiencing the effects of climate change, including increased precipitation, higher temperatures, and more extreme weather events. The city’s Climate Action Playbook outlines strategies to mitigate these impacts and adapt to a changing environment. Source
Understanding these evolving patterns is crucial for residents to prepare and adapt to Philadelphia’s changing climate.