September weather forecast
Pennsylvania, USA

As September unfolds in Pennsylvania, it marks the onset of autumn, introducing a refreshing blend of summer warmth and the crispness of fall. Temperatures typically range from 52°F (11.1°C) to 75°F (23.9°C), with the latter part of the month witnessing a more noticeable drop in temperatures. While daytime remains comfortably warm, evenings and early mornings take on a cooler persona, capturing the essence of fall.

September also ushers in the eagerly anticipated fall foliage. The state's landscapes transform with hues of amber, gold, and ruby, offering visually stunning panoramas, especially in the mountainous regions. Rainfall becomes less frequent, and when it does occur, it’s often lighter and more sporadic compared to the summer months. The drier climate, combined with the decreasing temperatures, sets the stage for the array of autumn festivals and outdoor events that the state is renowned for.

Areas close to Lake Erie, while experiencing the cooling trend, remain relatively milder, making them ideal for late summer beach visits or lakeside activities. In contrast, the higher altitudes, especially in the Appalachian region, showcase an earlier onset of fall colors, combined with slightly cooler temperatures.

In comparison to August, September is distinctively autumnal. While the former transitions from summer's peak to its decline, September embraces the fall spirit wholeheartedly. The days grow shorter, nights become crisper, and there's a general sense of transition as Pennsylvania prepares for the cooler months ahead. It's a month that offers a harmonious blend of the residual warmth of summer and the refreshing beginnings of autumn.

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• Philadelphia - September »
  In Philadelphia, Pennsylvania, during September, the rain falls for 10.5 days and regularly aggregates up to 0.87" (22mm) of precipitation. In Philadelphia in September, the average water temperature is 71.4°F (21.9°C).
• Pittsburgh - September »
  In Pittsburgh during September, the rain falls for 12.9 days and regularly aggregates up to 2.13" (54mm) of precipitation. September in Pittsburgh greets autumn with open arms, showcasing a steady decrease in temperatures, resulting in comfortable, moderate weather.
• Allentown - September »
  In Allentown, Pennsylvania, snow does not fall in June through September. In Allentown, Pennsylvania, in September, during 11.5 rainfall days, 1.61" (41mm) of precipitation is typically accumulated.
• Erie - September »
  The month with the least rainfall in Erie is September, when the rain falls for 7.9 days and typically collects 0.35" (9mm) of precipitation. In Erie during September, the rain falls for 7.9 days and regularly aggregates up to 0.35" (9mm) of precipitation.
• Reading - September »
  In Reading snow does not fall in June through September. September in Reading, Pennsylvania, highlights the turn of season with falling temperatures and reducing daylight hours.
• Scranton - September »
  The months with the least rainfall in Scranton are January and September Rain falls for 10.6 days and accumulates 1.38" (35mm) of rain. January and September are months with the least rain in Scranton when the rain falls for 10.6 days and typically aggregates up to 1.38" (35mm) of rain.
• Bethlehem - September »
  The month with the least rainfall in Bethlehem is September, when the rain falls for 11.8 days and typically collects 1.57" (40mm) of precipitation. The month with the least rainfall in Bethlehem is September, when the rain falls for 11.8 days and typically collects 1.57" (40mm) of precipitation.
• Lancaster - September »
  February and September are months with the least rain in Lancaster when the rain falls for 12.2 days and typically aggregates up to 1.89" (48mm) of rain. February and September are months with the least rain in Lancaster, Pennsylvania, when the rain falls for 12.2 days and typically aggregates up to 1.89" (48mm) of rain.
• Harrisburg - September »
  A subtle change in temperatures is noted in Harrisburg as August gives way to September, with average highs reducing from 81.5°F (27.5°C) to a still moderately hot 74.3°F (23.5°C). On the last day of September, in Harrisburg, sunrise is at 7:02 am and sunset at 6:52 pm EDT.
• Altoona - September »
  On the first day of September in Altoona sunrise is at 6:40 am and sunset at 7:46 pm. In Altoona, during September, the rain falls for 13.5 days and regularly aggregates up to 1.81" (46mm) of precipitation.
• York - September »
  In York, Pennsylvania, snow does not fall in May through September. On the first day of September in York, Pennsylvania, sunrise is at 6:34 am and sunset at 7:39 pm.
• State College - September »
  On the first day of September in State College, Pennsylvania, sunrise is at 6:38 am and sunset at 7:44 pm. In State College, Pennsylvania, in September, it is raining for 13.8 days, with typically 2.24" (57mm) of accumulated precipitation.