Last updated: February 24, 2025
September in Pittsburgh showcases a dynamic climate, where temperatures swing from a maximum of 34°C (93°F) to a refreshing minimum of 5°C (40°F), with an average of 20°C (68°F). The month experiences a notable 128 mm (5.0 in) of rainfall over 10 days, contributing to the 77% humidity that defines the transition from summer to fall. This blend of warmth and moisture creates an invigorating atmosphere, perfect for enjoying the city's vibrant outdoor scene and the early hints of autumn foliage.
September in Pittsburgh sees a delightful transition as summer gives way to fall. With minimum temperatures averaging 5°C (40°F) and daytime maxima reaching up to 34°C (93°F), the month is characterized by warm, comfortable days and cooler evenings. The overall average temperature hovers around 20°C (68°F), offering a beautiful balance that encourages outdoor activities. As the month progresses, the warmth gradually dissipates, hinting at the cooler days of October ahead. This shift not only marks a change in weather but also transforms the landscape, painting the region in vibrant autumn hues, making September a wonderful time to enjoy the natural beauty of Pittsburgh.
September in Pittsburgh typically brings a pleasant mix of rainfall, recording an average precipitation of 128 mm (5.0 in) over about 10 days. This sets the stage for a transition into the cooler autumn months, with precipitation amounts and rainy days decreasing compared to the lively summer season. Interestingly, September’s rainfall is on par with October, both sharing similar totals, but October sees a slight increase in rainy days. Overall, this month marks a gradual shift from the intense summer deluge, while still providing a healthy amount of moisture that supports the vibrant fall foliage that Pittsburgh is known for.
September in Pittsburgh brings a slight relief from the intense humidity of summer, with levels dropping to 77%. This shift marks the beginning of a seasonal trend where humidity gradually decreases as fall approaches. Throughout the summer months, humidity peaked at 82% in July, but by September, the air becomes noticeably crisper, paving the way for the cooler temperatures of autumn. Although humidity levels remain higher than those in the later fall months, this decrease hints at a gradual transition, leading into October's humidity of 82%, before the numbers rise again as winter sets in. Overall, September serves as a gentle bridge between the sultry heat of summer and the refreshing embrace of fall.
As summer gives way to autumn in Pittsburgh, the UV Index remains notably elevated in September, peaking at 8 on the scale, which classifies it as very high. This trend continues from the intense summer months, where the UV Index consistently reached a maximum of 10. Interestingly, despite the drop in temperatures, September's sun exposure still requires caution, with a burn time of just 15 minutes for fair-skinned individuals. This pattern highlights the importance of sun protection as the season transitions, reminding residents to stay vigilant against UV rays even as summer fades. For more detailed information, check the Pittsburgh UV Index.
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In September, Pittsburgh basks in the golden glow of 277 hours of sunshine, marking a delightful transition from the vibrant summer months. As we reflect on the year, it’s clear that this early autumn month gracefully follows the peak summer sunshine, which reaches its zenith in July with 332 hours. While the sun begins to make its subtle descent into the fall, September still enjoys significantly more light than the winter months ahead, particularly January’s paltry 104 hours. This month serves as a reminder of the lingering warmth before the days shorten and the chill sets in, making September a truly memorable time in the Steel City.
As September rolls in, Pittsburgh experiences a notable shift in its weather patterns, showcasing a 51% chance of sunny days. This increase marks a significant upward trend from the summer months, which hover around the mid to high 30s. Coming off the heels of August, where the sunshine probability sits at 38%, September promises more favorable weather, making it an ideal time for outdoor activities and enjoying the city's vibrant parks. The likelihood of sunshine begins to noticeably decline in October, making September a gem for those looking to soak in the last bits of summer warmth before fall sets in.
As the vibrant warmth of summer fades, September in Pittsburgh marks a transition with 12 hours of daylight. This reduction in sunlight from the previous month signifies the impending arrival of fall, as days gradually shorten from the peak of 15 hours in June. The city's daylight hours reflect a consistent pattern: starting from a mere 9 hours in January, the duration increases steadily until it reaches a summery high in June, before tapering off again into the shorter days of autumn and winter. This cyclical trend invites residents to embrace the last rays of summer while preparing for the cozy charm of the upcoming season.
As September unfolds in Pittsburgh, the transition from summer to autumn is marked by a subtle yet refreshing increase in wind speed, averaging 2.9 m/s (6 mph). This gentle breeze serves as a pleasant departure from the stillness of the hotter months, where wind speeds dipped as low as 2.0 m/s (4 mph) in August. While earlier months like January and March boast higher averages of 3.0 m/s (7 mph) and 3.5 m/s (8 mph) respectively, September's wind provides a moderate yet invigorating shift, hinting at the seasonal change ahead. As the city gears up for autumn, the slightly brisker air invites residents to enjoy outdoor activities while anticipating the vibrant foliage that accompanies the cooler days to come.
The weather in Pittsburgh 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 Pittsburgh and find detailed weather information for every month.
In September, temperatures in Pittsburgh range from a comfortable 5°C (40°F) at night to a warm 34°C (93°F) during the day, with an average of 20°C (68°F). The month sees significant rainfall, with about 128 mm (5.0 in) spread over 10 days and a humidity level of 77%, creating a pleasant yet occasionally damp atmosphere. Conversely, January brings a stark contrast, characterized by frigid temperatures that can drop as low as -22°C (-8°F) and an average of -1°C (31°F), with daytime highs reaching 21°C (70°F). Precipitation is less extensive at 95 mm (3.7 in) over 12 days, but the higher humidity at 88% contributes to the biting cold. For more details on January weather, you can visit Pittsburgh weather in January.
September and February present stark contrasts in weather patterns. In September, temperatures range from a mild 5°C (40°F) at night to a warm 34°C (93°F) during the day, with an average temperature of 20°C (68°F). The month experiences significant rainfall, totaling 128 mm (5.0 in) over about 10 days, combined with a humidity level of 77%. In contrast, February is much colder, with temperatures dipping as low as -20°C (-3°F) and averaging around 1°C (35°F). Although February's maximum temperature reaches 25°C (77°F), it also experiences high humidity at 88% and slightly less precipitation, totaling 125 mm (4.9 in) across 15 days. For more details on February weather, visit Pittsburgh weather in February.
When comparing the weather between September and March, it's clear that these months represent two very different seasons. In September, temperatures range from a mild 5°C (40°F) at night to a warm average of 20°C (68°F), peaking at highs of 34°C (93°F). In contrast, March experiences a much colder climate, with temperatures dipping as low as -17°C (1°F) and averaging only 5°C (42°F), albeit reaching a maximum of 25°C (78°F). Precipitation levels are relatively close, with September receiving 128 mm (5.0 in) over about 10 days, compared to March's 109 mm (4.3 in) spread across 13 days. Additionally, March tends to be more humid, with humidity levels reaching 87% compared to September's 77%. For a more detailed look at March weather dynamics in Pittsburgh, check out Pittsburgh weather in March.
When comparing the weather in September and April, notable differences emerge in temperature and overall climate conditions. September boasts a milder average temperature of 20°C (68°F), with highs reaching up to 34°C (93°F), making it feel much warmer compared to April, which has an average temperature of only 11°C (52°F) and a maximum of 29°C (84°F). Additionally, while September experiences less precipitation overall at 128 mm (5.0 in) across approximately 10 days, April sees a bit more rain at 132 mm (5.2 in) over 16 days, contributing to a higher humidity level of 87% compared to September's 77%. For more details on April weather, you can visit Pittsburgh weather in April.
When comparing the weather in September and May, several key differences emerge. September typically has a milder temperature range, with minimums of 5°C (40°F) and maximums reaching up to 34°C (93°F), averaging around 20°C (68°F). In contrast, May experiences cooler minimum temperatures that can drop to -2°C (29°F) but has similar highs of up to 31°C (89°F) with an average of 17°C (63°F). Precipitation is more frequent in May, with rain falling on about 17 days and totaling 150 mm (5.9 in), compared to September's 10 rainy days and 128 mm (5.0 in). Additionally, humidity levels are slightly higher in May at 81%, as opposed to September’s 77%. For more detailed information, visit Pittsburgh weather in May.
In comparing the weather between September and June, we see some notable differences. September experiences a slightly lower average temperature of 20°C (68°F) compared to June's 21°C (70°F), although both months have similar minimum temperatures of 5°C (40°F) to 5°C (41°F). The maximum temperatures are also comparable, with September peaking at 34°C (93°F) and June reaching 33°C (92°F). However, September tends to be wetter, receiving 128 mm (5.0 in) of precipitation over 10 days, while June has a higher rainfall of 155 mm (6.1 in) spread over 16 days. Additionally, humidity levels are slightly elevated in June at 83%, compared to 77% in September. For a more detailed look at June weather, you can check out Pittsburgh weather in June.
In comparing the weather of September and July, we can see distinct differences in temperature and precipitation patterns. September experiences a broader range of temperatures with a minimum of 5°C, an average of 20°C, and a maximum of 34°C, while July tends to be warmer overall, with minimums around 12°C, averages of 24°C, and highs reaching 35°C. Additionally, September is slightly drier, receiving 128 mm of precipitation over 10 days compared to July's 154 mm over 15 days. Humidity levels are a bit lower in September at 77%, compared to July's 82%. For a more detailed look at July weather specifically, you can visit Pittsburgh weather in July.
In comparing the weather of September to August, we see some notable differences. September experiences a lower minimum temperature of around 5°C (40°F), while August starts at a warmer 11°C (52°F). The average temperature in September is slightly cooler at 20°C (68°F), compared to August's average of 23°C (73°F). Both months can reach a maximum of 34°C (93°F), but September is characterized by higher precipitation at 128 mm (5.0 in) over about 10 days, compared to August's 89 mm (3.5 in) over 16 days. Humidity levels remain comparable, with September at 77% and August at 76%. For more detailed insights, you can visit Pittsburgh weather in August.
In September, the weather tends to be warmer, with average temperatures around 20°C (68°F) and a maximum reaching up to 34°C (93°F). The month also experiences significant rainfall, totaling 128 mm (5.0 in) over about 10 days, with humidity levels averaging 77%. In contrast, October brings a notable drop in temperatures, with minimums dipping to -1°C (31°F) and an average of 14°C (57°F), while the maximums remain similar at 31°C (89°F). The precipitation remains the same at 128 mm (5.0 in), but it's spread over 14 days, resulting in slightly higher humidity at 82%. For more details about October weather in Pittsburgh, visit Pittsburgh weather in October.
September and November exhibit contrasting weather patterns, reflecting the transition from late summer to late fall. In September, temperatures range dramatically from a minimum of 5°C (40°F) to a maximum of 34°C (93°F), with an average temperature of 20°C (68°F), while November sees a much cooler temperature range, with a minimum of -13°C (9°F) and a maximum of 25°C (78°F), and an average of just 5°C (42°F). Precipitation levels are slightly higher in September at 128 mm (5.0 in) over 10 days compared to November's 94 mm (3.7 in) over 11 days. Additionally, November experiences higher humidity levels at 89%, compared to September's 77%. For more detailed insights into the weather in November, check out Pittsburgh weather in November.
Comparing the weather in September and December reveals a dramatic shift in temperatures and conditions. September enjoys a wide temperature range, with averages around 20°C (68°F) and peaks reaching up to 34°C (93°F), accompanied by substantial rainfall of 128 mm over approximately 10 days. In contrast, December is characterized by much colder temperatures, with an average of just 2°C (36°F) and minimums plummeting to -16°C (4°F). While December has slightly less precipitation at 102 mm over 12 days, the humidity rises to 86%, making it feel even colder. For more details on the December climate, visit Pittsburgh weather in December.
As summer transitions to fall, September in Pittsburgh offers a captivating blend of warm days and cooler nights. The month features a comfortable average temperature, making it a delightful time for outdoor activities. While the humidity remains relatively high, the rainfall, though noticeable, is less frequent than in the peak of summer, marking a shift towards drier days. This harmonious mix sets September apart from the sweltering heat of July and the unpredictable weather of October. For more detailed insights on how Pittsburgh’s weather shapes its vibrant atmosphere, explore the Pittsburgh Climate.