Last updated: February 24, 2025
September in Philadelphia brings a delightful mix of warm temperatures and refreshing breezes. With a maximum temperature reaching 32°C (89°F), the month is marked by an average of 17°C (62°F), while minimum temperatures can dip to a cool 0°C (33°F). Visitors can expect around 75 mm (3.0 in) of precipitation spread over 9 days, contributing to the city's lush greenery. The humidity levels hover around 72%, creating a comfortable atmosphere perfect for enjoying the city's vibrant parks and outdoor activities.
As September rolls in, Philadelphia transitions into a crisp autumn feel, with temperatures reflecting this shift. The month starts off with a minimum of 0°C (33°F), providing a refreshing contrast to the lingering warmth of summer. The average temperature settles at 17°C (62°F), creating pleasant days ideal for outdoor activities, while the highs can still reach a comfortable 32°C (89°F). This fluctuation highlights the city's unique climate, where the last remnants of summer intertwine with the cool promise of fall. As the month progresses, residents and visitors alike can enjoy the vibrant foliage and the gradual drop in temperature, setting the stage for the cozy months ahead.
In September, Philadelphia experiences a notable shift in precipitation patterns, with an average rainfall of 75 mm (3.0 in) over just 9 days. This marks a decrease compared to the wetter summer months, where July and August see averages of 137 mm (5.4 in) and 106 mm (4.2 in), respectively. As summer transitions into fall, the lighter rainfall signals a gradual decline in moisture, paving the way for October’s more substantial average of 160 mm (6.3 in). This September dip in both precipitation amount and rainy days presents an inviting opportunity for outdoor activities, as the city enjoys clearer skies and milder temperatures, creating a perfect backdrop for early autumn adventures.
As summer fades into autumn, September in Philadelphia experiences a moderate dip in humidity, settling at 72%. This change marks a slight increase from the drier months of June (68%) and August (67%), while still being notably lower than the winter months, where humidity levels climb to 93% in both January and February. The transition reflects the city's temperate climate, with fall approaching and heralding a gradual rise in moisture as the year progresses. Notably, October sees a significant jump back to 83%, suggesting that the crisp air of fall comes with a touch of humidity that keeps the atmosphere rich and vibrant. Overall, Philadelphia's humidity trend showcases a rhythmic pattern influenced by seasonal shifts, creating a unique climate throughout the year.
As September rolls into Philadelphia, the UV Index reflects a transition from the peak summer months, registering at 7 and placing it in the high exposure category. This represents a slight decrease from the previous months, which consistently hovered at a challenging 9. With a burn time of just 25 minutes, it's essential to remain vigilant about sun protection, especially during midday hours. September signals the onset of fall, yet UV levels still call for caution, reminding us that even as temperatures begin to cool, sunlight can still pose risks. For more details on UV exposure in the city, check Philadelphia UV Index.
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As the summer fades into autumn, September in Philadelphia greets residents with a delightful 281 hours of sunshine, a vibrant farewell to the warm months. This figure, while less than the sun-drenched peak of 339 hours in July, still reflects a significant abundance of light as the city transitions from the sweltering summer heat. With a progressive drop in hours from the scorching 326 hours of August, September's sunshine lays the groundwork for the crispness of October, which offers a cozy 194 hours. This gradual decline in sunlight mirrors the changing seasons, encouraging Philadelphians to savor the lingering warmth before the shorter days set in. Overall, September stands out as a radiant bridge between summer’s vibrant glow and the cool autumn days ahead.
September in Philadelphia offers a welcoming 40% chance of sunny weather, positioning it as a favorable month for outdoor activities. This is notably higher than the early months of the year, such as January and February, where sunshine is scarce at 24% and 26%, respectively. As the city transitions through the summer, the likelihood of sun peaks in August at 42%, before slightly dipping in September. Overall, the trend reveals a comfortable balance of sunny days as summer wanes and fall approaches, making September an ideal time to enjoy the outdoors before the cooler months set in.
As summer transitions into fall, September in Philadelphia marks a subtle shift in daylight duration, offering around 12 hours of sunlight. This month sees a gradual decrease from the peak of 15 hours in June and July, reflecting the approaching autumn. September's length of daylight continues the trend established in the earlier months of the year, where it consistently increases from a brief 9 hours in January to spring's robust 14 hours in May. As the city prepares for the cooler months ahead, the diminishing daylight serves as a gentle reminder of nature's rhythms, leading to shorter days and longer nights as October approaches, where daylight plummets to 10 hours.
As September unfolds in Philadelphia, the city experiences a pleasant breeze with an average wind speed of 3.2 m/s (7 mph), setting the stage for the arrival of autumn. Compared to the preceding summer months, where the winds languished around 2.6 m/s, this uptick brings a refreshing change, encouraging residents to embrace outdoor activities. Interestingly, September's winds mirror those of February, suggesting a seasonal symmetry as the year transitions. As the days grow shorter and cooler, the wind speeds remain fairly steady, hinting at the stability of weather patterns as fall approaches. This gentle gustiness not only enhances the city's vibrant atmosphere but also foreshadows the crispness of October still to come.
The weather in Philadelphia changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Philadelphia and find detailed weather information for every month.
September and January present striking contrasts in weather conditions. In September, temperatures range from a minimum of 0°C (33°F) to a maximum of 32°C (89°F), with an average of 17°C (62°F). The month experiences about 75 mm (3.0 in) of precipitation over approximately 9 days, and the humidity hovers around 72%. In stark contrast, January brings frigid conditions with temperatures plunging to a minimum of -33°C (-27°F) and averaging -6°C (22°F), peaking at just 14°C (58°F). Precipitation in January totals 86 mm (3.4 in) distributed over about 12 days, and the humidity is notably higher at 93%. For more details, you can check Philadelphia weather in January.
September and February present starkly contrasting weather conditions. In September, temperatures range from a pleasant 0°C (33°F) at night to a warm 32°C (89°F) during the day, with an average of 17°C (62°F). The month experiences a moderate amount of precipitation, totaling 75 mm (3.0 in) over about 9 days, with humidity levels around 72%. In contrast, February brings much colder temperatures, with nighttime lows plunging to -27°C (-16°F) and daytime highs reaching a mere 15°C (60°F), averaging -4°C (25°F). This winter month has slightly higher precipitation at 84 mm (3.3 in) spread across about 12 days, accompanied by higher humidity at 93%. To better understand the chilly conditions, you can visit Philadelphia weather in February.
In comparing the weather between September and March, a stark contrast emerges. September boasts milder temperatures, with a minimum of 0°C (33°F) and an average of 17°C (62°F), reaching a maximum of 32°C (89°F). This month experiences around 75 mm (3.0 in) of precipitation over 9 days, and humidity levels are at a comfortable 72%. In contrast, March brings much colder conditions, with minimum temperatures dipping to -22°C (-7°F) and an average of just 0°C (32°F). While the maximum temperature is higher at 21°C (70°F), March sees slightly increased precipitation at 88 mm (3.5 in) across 12 days, alongside higher humidity at 86%. For a deeper insight into the nuances of March weather, visit Philadelphia weather in March.
When comparing the weather in September and April, notable differences emerge in both temperature and precipitation levels. September boasts a more moderate temperature range, with minimums around 0°C (33°F) and maximums reaching 32°C (89°F), contributing to an average of 17°C (62°F). In contrast, April experiences a chillier climate, with minimum temperatures dropping to -7°C (19°F) and an average of only 7°C (44°F), although it can still peak at 30°C (86°F).
Precipitation is another key factor; September sees about 75 mm (3.0 in) over approximately 9 days, while April typically has higher rainfall, totaling 130 mm (5.1 in) across 14 days. Additionally, humidity levels are slightly elevated in April at 82%, compared to 72% in September. For more detailed information, you can visit Philadelphia weather in April.
In September, temperatures in Philadelphia range from a chilly 0°C (33°F) at night to a warm 32°C (89°F) during the day, with an average of 17°C (62°F). The month sees about 75 mm (3.0 in) of precipitation spread over 9 days, accompanied by a humidity level of 72%. In contrast, May features slightly cooler temperatures, with nighttime lows dipping to -2°C (29°F) and daytime highs reaching 32°C (90°F), while the overall average hovers around 14°C (57°F). However, May brings more rainfall, totaling 104 mm (4.1 in) over 13 days, and maintains a higher humidity at 75%. The difference in weather patterns highlights the transition from summer to fall, making these months distinctly unique. For more details, you can check Philadelphia weather in May.
September and June exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 0°C (33°F) to a maximum of 32°C (89°F), with an average of 17°C (62°F). The month sees around 75 mm (3.0 in) of precipitation over approximately 9 days and maintains a humidity level of 72%. In contrast, June starts off slightly warmer, with temperatures ranging from a minimum of 3°C (38°F) to a peak similar to September at 32°C (90°F) and an average of 19°C (66°F). However, June is wetter, receiving 104 mm (4.1 in) of rain over about 13 days, and features slightly lower humidity at 68%. For more detailed insights, you can check Philadelphia weather in June.
When comparing the weather in September to July, several key differences emerge. September features a wider temperature range, with minimums dropping to 0°C (33°F) and maximums reaching up to 32°C (89°F), while July maintains milder lows of 9°C (49°F) and higher highs at 35°C (95°F). In terms of average temperatures, September's average is 17°C (62°F), compared to July's warmer average of 22°C (72°F). Additionally, September experiences significantly less precipitation, totaling 75 mm (3.0 in) over 9 days, while July sees more rain with 137 mm (5.4 in) over 14 days, contributing to a slightly drier atmosphere in September despite its higher humidity level of 72%. For a closer look at July's specific conditions, you can check out Philadelphia weather in July.
September sees a notable shift in weather compared to August. While August enjoys warmer average temperatures of around 21°C (70°F) with a minimum of 7°C (44°F), September drops to an average of 17°C (62°F) and a cooler minimum of 0°C (33°F). Though both months experience maximum temperatures of 89°F (31°C in August and 32°C in September), September is characterized by increased rainfall, totaling 75 mm (3.0 in) over 9 days compared to August's 106 mm (4.2 in) over 14 days. Additionally, September maintains a higher humidity level at 72%, slightly above August's 67%. For a closer look at August's climate, you can explore Philadelphia weather in August.
September typically experiences warmer temperatures, with an average of 17°C (62°F) and maximum highs reaching 32°C (89°F), contrasting sharply with October's cooler average of 11°C (52°F) and maximums of 26°C (80°F). The precipitation levels also rise in October, with 160 mm (6.3 in) falling over 14 days, compared to September's 75 mm (3.0 in) across 9 days. Additionally, October tends to be more humid, averaging 83% compared to September's 72%. For more detailed insights, check out Philadelphia weather in October.
September and November exhibit striking differences in weather patterns. In September, temperatures range from a pleasant minimum of 0°C (33°F) to a maximum of 32°C (89°F), with an average of 17°C (62°F). This month typically experiences about 75 mm (3.0 in) of precipitation over 9 days, accompanied by a humidity level of 72%. Conversely, November brings much colder conditions, with temperatures dipping as low as -15°C (6°F) and averaging just 3°C (37°F). The maximum temperature can reach 22°C (73°F), but overall, November is characterized by increased precipitation of 119 mm (4.7 in) over 14 days and higher humidity at 88%. For a detailed look at what to expect, check out Philadelphia weather in November.
September and December exhibit stark contrasts in weather conditions. In September, temperatures range significantly, with a minimum of 0°C (33°F) and a maximum soaring to 32°C (89°F), while the average temperature hovers around a mild 17°C (62°F). The month sees about 75 mm (3.0 in) of precipitation over 9 days, accompanied by a humidity level of 72%. In contrast, December brings much colder temperatures, with a minimum plunging to -27°C (-17°F) and an average temperature of -2°C (28°F). The maximum during this month is a mere 16°C (61°F). Additionally, December experiences more precipitation, totaling 98 mm (3.8 in) over 13 days, and a higher humidity of 89%. For a deeper look into conditions, check Philadelphia weather in December.
As September unfolds in Philadelphia, the city's weather transitions into a moderate mix of warmth and mildness, offering a refreshing change from the summer heat. With average temperatures settling around a comfortable 17°C, the days can still reach balmy highs of 32°C while occasionally dipping to cooler nights. This month also brings a touch of humidity at 72% and some rainfall, averaging 75 mm spread over about 9 days, marking a shift from the typically dry summer months. Embrace the pleasant conditions that September offers, making it an ideal time to explore the vibrant city before the chill of fall sets in. For a deeper understanding of seasonal trends, explore the full details at Philadelphia Climate.