Last updated: February 24, 2025
In September, Mount Vernon, United States, experiences a diverse climate characterized by warm temperatures and substantial humidity. The month sees a maximum temperature reaching 33°C (92°F), while the average daily temperature hovers around a comfortable 23°C (74°F). On cooler days, temperatures can dip to a minimum of 11°C (51°F), providing a pleasant contrast. Rainfall is a notable feature, with approximately 100 mm (3.9 in) of precipitation spread across 10 days, resulting in a humidity level of 75% that often enhances the lush scenery of the area. Prepare for a mix of sunny spells and refreshing showers as you enjoy the vibrant transition into autumn!
As September arrives in Mount Vernon, temperatures begin to shift towards the crispness of fall while still holding on to the warmth of summer. With a minimum of 11°C (51°F) and an average of 23°C (74°F), days remain pleasantly warm, peaking at a maximum of 33°C (92°F). This month marks a smooth transition, as evenings cool down, inviting cozy sweaters and bonfire gatherings. Unlike the sweltering July and August, September balances warmth with a gentle breeze, making it a delightful time to explore the changing foliage and enjoy outdoor activities before autumn fully sets in. This gradual descent in temperature foreshadows the cooler months ahead while still offering a taste of summer's lingering embrace.
In September, Mount Vernon experiences a notable shift in its precipitation patterns, with an average of 100 mm (3.9 in) of rain spread over approximately 10 days. This brings a welcome respite from the higher rainfall of the summer months, as both July and August saw significant downpours of 139 mm and 149 mm respectively. The transition into autumn marks a decline in precipitation days, with September having fewer rainy days compared to the peak rainfall months. As the year progresses toward October and November, precipitation tends to stabilize, suggesting a gradual yet persistent pattern of wetter conditions in the preceding summer months before easing into the fall. This seasonal rhythm not only influences the region's climate but also shapes the lush landscapes that characterize Mount Vernon at this time of year.
September marks a subtle transition in Mount Vernon's humidity levels, settling at 75%. This reflects a noteworthy decline from the summer months, where humidity hit its lowest in August at 72%. As the seasons shift towards autumn, the increase in humidity associated with the cooler days of October and November—rising back to 81% and 85%, respectively—is evident. Overall, September serves as a bridge, balancing the fading summer warmth with the impending crispness of fall, showcasing a gentle rise from earlier summer lows while still being significantly lower than the winter months' averages that hover around 84%.
As summer fades into early autumn, September in Mount Vernon showcases a significant drop from the peak UV Index of 10 in the preceding months, settling at 8, which still falls into the very high exposure category. This indicates that while the burning time remains notably brisk at just 15 minutes, residents and visitors alike should continue to prioritize sun safety. Interestingly, the trend observed from April through August, with their increasing UV Index values, slightly decreases this month, hinting at a seasonal transition. However, with a still elevated UV Index, it’s essential to stay vigilant. For an in-depth look into sun exposure trends throughout the year, explore the Mount Vernon UV Index.
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In Mount Vernon, the month of September shines brightly with an impressive 294 hours of sunshine, contributing to a gradual decline from the peak of summer. The trend reveals a steady increase in sunlight from the depths of winter, where January struggles with just 161 hours. As warmer months approach, sunlight flourishes, peaking in July with a remarkable 366 hours. Following this vibrant summer, September still holds its own, offering ample sunshine compared to the autumn months ahead. This sunny trend begins to wane as October sees a significant drop to 260 hours, indicating a transition into the cozy, cooler days of fall. Such a pattern not only enhances the beauty of Mount Vernon but also invites residents and visitors alike to revel in the rich tapestry of seasonal transformations.
September in Mount Vernon, United States, ushers in a notable 58% chance of sunny weather, marking it as one of the sunniest months of the year. This uptick in sunshine contrasts with the more overcast summer months, where July and August dip to 51% and 37% respectively. As autumn approaches, the likelihood of sunny days tends to increase, showing a clear trend as we transition from the high humidity of summer into the crispness of fall. With this perfect blend of warmth and brightness, September stands out as an ideal time for outdoor activities, inviting residents and visitors alike to savor the changing season under clear skies.
As September rolls into Mount Vernon, the days gradually shorten, with daylight lasting 12 hours. This transition marks a subtle shift from the sun-drenched peak of summer, where July and June bask in an abundant 14 hours of light. As we reflect on the month-by-month journey, it’s clear that spring welcomes longer days, peaking in late spring and summer, before gently descending into the cozy embrace of autumn. With the 12 hours of daylight in September, residents begin to notice the crispness in the air, hinting at the imminent arrival of fall, while still enjoying the warmth of the day—truly a delightful blend of lingering summer and the promise of seasonal change.
As September arrives in Mount Vernon, the wind continues to dance gently through the landscape, averaging 3.5 m/s (8 mph). This slight uptick from the languid breezes of August reflects a transition toward the crisper autumn air. Observing the trends throughout the year, one can note the wind speeds consistently hovered around 3.5 to 4.1 m/s from January through April, peaking in spring before gradually tapering off during the summer months. The gentle breeze of September feels like a breath of fresh air, as it mirrors the seasonal shift with a return to more inviting winds that will soon prepare the region for the brisker gales of fall. This month symbolizes not just a change in temperature, but a refreshing reminder of nature's ebb and flow, setting the stage for the months to come.
The weather in Mount Vernon 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 Mount Vernon and find detailed weather information for every month.
September and January present strikingly different weather patterns. In September, temperatures typically range from a minimum of 11°C (51°F) to a maximum of 33°C (92°F), with an average of 23°C (74°F). The month experiences around 100 mm (3.9 in) of precipitation over approximately 10 days, accompanied by a relative humidity of 75%.
In contrast, January sees significantly colder temperatures, with a minimum of -16°C (3°F) and a maximum reaching 20°C (69°F), averaging just 4°C (39°F). Precipitation in January is lower at 71 mm (2.8 in), spread over about 9 days, while humidity rises to 84%. For more details, you can check Mount Vernon weather in January.
September and February showcase stark contrasts in weather conditions. September typically experiences much milder temperatures, averaging 23°C (74°F) with highs reaching up to 33°C (92°F), while February is colder, with an average of 6°C (43°F) and minimum temperatures plummeting to -11°C (12°F). Both months see similar levels of precipitation, with September receiving about 100 mm (3.9 in) and February slightly less at 94 mm (3.7 in), though February has one more day of precipitation. Additionally, humidity levels are higher in February at 83%, compared to September's 75%, resulting in a chillier, more damp atmosphere. For a more detailed look at February weather, visit Mount Vernon weather in February.
September and March present contrasting weather patterns, highlighting the transition between summer and early spring. In September, temperatures range from a mild 11°C (51°F) at night to a warm 33°C (92°F) during the day, with an average of 23°C (74°F). The month experiences around 100 mm (3.9 in) of precipitation over approximately 10 days, accompanied by a humidity level of 75%. In contrast, March sees much cooler temperatures, with nighttime lows plunging to -6°C (22°F) and a maximum of 28°C (83°F), yielding an average of only 9°C (48°F). Despite being drier, it still receives 91 mm (3.6 in) of rain over the same number of days, coupled with a slightly higher humidity of 83%. For a deeper understanding of March weather trends, check out Mount Vernon weather in March.
In comparing the weather of September and April, we observe distinct seasonal differences. September tends to be warmer, with average temperatures around 23°C (74°F) and maximums reaching up to 33°C (92°F), while April's temperatures are cooler, averaging 14°C (58°F) and peaking at 30°C (87°F). Although September experiences slightly more precipitation (100 mm) over about 10 days, April is not far behind with 88 mm of rain across 11 days. Additionally, humidity levels are notably high during both months, with September at 75% and April at 81%. For more detailed insights, you can check Mount Vernon weather in April.
September and May present notable differences in weather despite their similar maximum temperatures. In September, the minimum temperature is warmer at 11°C (51°F), with an average of 23°C (74°F) and a maximum reaching 33°C (92°F), combined with a humid 75% average humidity. The month sees around 100 mm (3.9 in) of precipitation over approximately 10 days. In contrast, May starts off cooler, with a minimum of 5°C (42°F) and an average of 19°C (67°F), while still hitting a maximum of 33°C (91°F). Rainfall is slightly higher at 104 mm (4.1 in) over 11 days, and humidity is a bit higher at 78%. For more specific insights into the weather patterns of May, please visit Mount Vernon weather in May.
September and June present similar temperature extremes, with both months reaching a maximum of 33°C (91°F) to 33°C (92°F) on hot days. However, the average temperatures are slightly cooler in September, with a minimum of 11°C (51°F) compared to June's 12°C (54°F). Precipitation levels are also quite close, with September receiving 100 mm (3.9 in) over approximately 10 days, while June has a slightly higher total of 106 mm (4.2 in) over 12 days. The humidity is marginally lower in September at 75%, compared to June's 79%, making September feel a bit more comfortable overall. For a detailed look at June weather patterns, check out Mount Vernon weather in June.
In comparing the weather of September and July, September boasts a wider temperature range with minimums of 11°C (51°F) and highs reaching 33°C (92°F), averaging around 23°C (74°F). In contrast, July generally experiences warmer conditions, with minimum temperatures at 15°C (60°F) and maximums peaking at 37°C (98°F), averaging 27°C (81°F). Additionally, July tends to be wetter, receiving 139 mm (5.5 in) of precipitation over 13 days compared to September's 100 mm (3.9 in) over 10 days. While both months feature high humidity levels, September is slightly more humid at 75%, while July has a humidity level of 74%. For a detailed look, visit Mount Vernon weather in July.
In comparing the weather patterns of September and August, September generally experiences slightly cooler temperatures, with a minimum of 11°C (51°F) and a maximum of 33°C (92°F), while August sees warmer minimums at 17°C (63°F) and maximums up to 35°C (95°F). The average temperature in September is 23°C (74°F), compared to August’s 26°C (79°F). Rainfall is notably less in September, with total precipitation at 100 mm (3.9 in) over 10 days, in contrast to August’s 149 mm (5.8 in) over 15 days. Humidity levels are relatively similar, with September at 75% and August slightly lower at 72%. For more details on the specific weather conditions in August, you can check Mount Vernon weather in August.
In comparing the weather of September and October, we see a marked transition as autumn sets in. September boasts warmer daytime temperatures, with an average of 23°C (74°F) and highs reaching up to 33°C (92°F), while October's average drops to a cooler 18°C (64°F) with a maximum of 32°C (91°F). Both months experience significant humidity, with October slightly higher at 81% compared to September's 75%. Precipitation also increases into October, totaling 117 mm (4.6 in) over 9 days, while September records 100 mm (3.9 in) over 10 days. For more insights on October weather specifics, check out Mount Vernon weather in October.
September and November present striking contrasts in weather patterns. September boasts warmer temperatures, with a minimum of 11°C (51°F), an average of 23°C (74°F), and maximum highs reaching 33°C (92°F). The month experiences approximately 100 mm (3.9 in) of precipitation over 10 days and maintains a humidity level of 75%. In contrast, November sees much cooler temperatures, with a minimum of -4°C (24°F), an average of 10°C (50°F), and a maximum of 25°C (77°F). This month also has slightly less precipitation at 84 mm (3.3 in) over 8 days while humidity rises to 85%. For a closer look at November weather specifics, check out Mount Vernon weather in November.
September and December present contrasting weather conditions. In September, temperatures range from a minimum of 11°C (51°F) to a maximum of 33°C (92°F), with an average of 23°C (74°F), making it a warm month with relatively high humidity at 75%. It experiences about 100 mm (3.9 in) of precipitation over approximately 10 days.
In contrast, December brings much cooler temperatures, dropping to a minimum of -9°C (16°F) and averaging around 6°C (44°F), while the maximum reaches only 21°C (69°F). The month is slightly less wet, with around 97 mm (3.8 in) of precipitation also spread over 10 days, and the humidity increases to 84%. For more detailed information about December weather, you can visit Mount Vernon weather in December.
As September rolls into Mount Vernon, the weather showcases a delightful transition from the intense summer heat to more temperate conditions. With average temperatures settling around a pleasant 23°C (74°F), the month offers a comfortable reprieve from the scorching highs of summer. However, don't be surprised by occasional rain, as September tends to bring more humidity and about ten days of precipitation, contributing to its lush landscape. This unique blend of warm days and cooler nights makes September an ideal time for outdoor activities, marking a significant departure from the peak summer days. For a deeper understanding of what to expect throughout the year, check out Mount Vernon Climate.