September in Pennsylvania typically marks a transition from summer’s heat to autumn’s cooler temperatures. This period experiences decreasing humidity and increasingly pleasant days, alongside gradually shortening daylight hours. Average high temperatures across the state range from the low 70s Fahrenheit (low 20s Celsius) in the northern mountainous regions to the low 80s Fahrenheit (high 20s Celsius) in the southeastern corner. Overnight lows generally fall into the 50s Fahrenheit (10-15 Celsius). Rainfall amounts remain relatively consistent with summer levels.
Understanding Pennsylvania’s climate during this month is crucial for various activities, including agriculture, tourism, and outdoor recreation. Farmers rely on these moderate temperatures and rainfall patterns for successful harvests. The pleasant weather also draws tourists eager to experience the state’s vibrant fall foliage as it begins to emerge. Moreover, the comfortable conditions are ideal for outdoor pursuits such as hiking, biking, and camping. This seasonal shift historically signifies the end of the growing season in many parts of the state and the beginning of preparations for winter.