Last updated: February 24, 2025
In Mount Vernon during September, the climate showcases a dramatic range in temperatures, with a maximum reaching 37°C (99°F) and a minimum dipping to 6°C (44°F). On average, the month enjoys a comfortable 22°C (73°F), making it a pleasant time to experience the region. However, this comfort comes with an average precipitation of 93 mm (3.7 in) spread over 11 days, resulting in a humidity level of around 75%. Whether basking in the warmth or navigating the occasional rain, September in Mount Vernon offers diverse weather experiences that cater to all preferences.
In September, Mount Vernon experiences a delightful transition from the sweltering summer heat to more moderate temperatures. The average temperature settles at a comfortable 22°C (73°F), with nighttime lows dipping to around 6°C (44°F), showcasing the cool, crisp air that begins to herald the arrival of autumn. Daytime highs can still reach a balmy 37°C (99°F), providing perfect opportunities for outdoor activities as the summer's intensity wanes. This month marks a gradual decline from the peak summer temperatures of July and August, reflecting a broader trend of cooling as the year progresses. The balance of warmth during the day and refreshing cooler nights makes September a particularly enjoyable time in Mount Vernon.
In September, Mount Vernon experiences a notable shift in weather patterns, with precipitation amounting to 93 mm (3.7 in) over 11 days. This marks a decrease from the heavy rainfall in the preceding months of July and August, where totals reached 132 mm (5.2 in) and 146 mm (5.7 in), respectively. The fall transition introduces more moderate rains compared to the summer peak, hinting at the impending change of seasons. With rainfall decreasing yet remaining consistent, September sets the stage for the autumn months, where average precipitation begins to stabilize around 105 mm in October before tapering off as winter approaches.
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 September rolls into Mount Vernon, residents can expect a UV Index of 8, indicating a very high exposure category with a burn time of just 15 minutes. This trend marks a slight decline from the peak summer months, where the UV Index consistently hit 10. However, it remains crucial to stay vigilant, as the lingering summer sun continues to pose a threat. Comparatively, the month follows a pattern of high UV exposure seen since April, emphasizing the importance of sun protection as we transition into fall. Keep this in mind for outdoor activities, and stay informed with the latest updates on the Mount Vernon UV Index.
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As summer gracefully transitions into autumn, September shines brightly in Mount Vernon with an impressive 276 hours of sunshine. This month reflects a gradual decline from the peak summer moments of July, basking in a glorious 357 hours, and August's strong 321 hours. While daylight hours decrease, the lingering warmth provides a beautiful backdrop for outdoor activities, reminiscent of the sun-drenched days preceding it. September’s sunshine still offers a vibrant ambiance, hinting at the coziness of fall while reminding residents of the abundant daylight that characterized the previous months. As the season shifts, one can sense the rhythm of nature, with September serving as a gentle bridge between the fiery summer and the crispness of autumn.
In Mount Vernon, United States, September stands out as a month with a 55% chance of sunny weather, marking it as a promising time for outdoor activities. This reflects a noticeable upward trend compared to the summer months, particularly August, which has only a 35% chance of sunshine. As the year progresses into fall, September's likelihood of sun exceeds that of the surrounding months, with only November surpassing it at 58%. This increase in sunny days provides a delightful opportunity for residents and visitors alike to enjoy the transition into autumn amidst relatively clear skies. Overall, September offers a perfect blend of warmth and sunshine, making it one of the more favorable months in the region’s climate calendar.
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 summer transitions into fall, September winds in Mount Vernon offer a gentle respite, with an average speed of 2.5 m/s (6 mph). This marks a slight uptick from the languid breezes of August, which saw winds drop to their year-low of 1.9 m/s (4 mph). The return of more robust winds signifies a shift in the seasons, as nature begins to ready itself for autumn’s approach. Looking back, the months leading to September show a consistent decline in wind speed from a peak during the spring months, reflecting the calming effects of summer heat. As October draws near, residents can expect similar conditions, with winds projected to pick up slightly to 2.7 m/s (6 mph), creating a pleasant ambiance perfect for outdoor activities amidst the changing foliage.
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 exhibit stark contrasts in weather conditions. In September, temperatures can range from a pleasant 22°C (73°F) on average to a blistering high of 37°C (99°F), accompanied by relatively high humidity at 75%. The month sees considerable rainfall, with an average of 93 mm (3.7 in) over about 11 days. In contrast, January experiences much colder temperatures, with an average of just 3°C (38°F) and lows plunging to -14°C (7°F). The month is drier, with only 61 mm (2.4 in) of precipitation spread over 7 days, yet it has a higher humidity level at 84%. For more detailed insights into January weather specifically, you can explore Mount Vernon weather in January.
September and February present contrasting weather patterns, showcasing the extremes of the seasons. In September, temperatures range from a minimum of 6°C (44°F) to a scorching maximum of 37°C (99°F), with an average of 22°C (73°F). The month experiences 93 mm (3.7 in) of precipitation over 11 days, and humidity sits at a comfortable 75%. In stark contrast, February features much colder conditions, with temperatures ranging from a minimum of -14°C (7°F) to a maximum of 27°C (81°F), averaging at just 5°C (42°F). Similar to September, February also sees 96 mm (3.8 in) of precipitation over 11 days, but with higher humidity at 83%. For a closer look at February weather specifics, you can visit Mount Vernon weather in February.
When comparing the weather in September and March, September boasts a warmer climate with average temperatures reaching 22°C (73°F) and maximum highs often soaring to 37°C (99°F). In contrast, March experiences cooler temperatures, with averages around 8°C (47°F) and occasional highs of up to 29°C (84°F). Both months have similar precipitation levels, with September receiving 93 mm (3.7 in) over 11 days and March seeing slightly less at 82 mm (3.2 in) over 9 days. Additionally, March tends to be slightly more humid, averaging 83% compared to September's 75%. For more detailed information about March weather, you can visit Mount Vernon weather in March.
When comparing September and April weather, there are notable differences in temperature and precipitation. September typically boasts warmer averages, with temperatures ranging from a minimum of 6°C (44°F) to a maximum of 37°C (99°F), while April experiences cooler conditions, with temperatures dipping as low as -1°C (31°F) and reaching a maximum of 33°C (92°F). Both months have similar precipitation patterns, receiving around 93 mm (3.7 in) in September and 102 mm (4.0 in) in April, each with rainfall occurring on approximately 11 days. Despite the slightly higher precipitation in April, the humidity is marginally greater at 81% compared to September's 75%. For more detailed information, you can explore Mount Vernon weather in April.
September and May present a noticeable contrast in weather patterns. September features a wider temperature range, with minimums around 6°C (44°F) and maximums reaching up to 37°C (99°F), while May has slightly cooler temperatures, ranging from 3°C (37°F) to a maximum of 35°C (95°F). Precipitation in May is slightly higher at 121 mm (4.8 in) compared to September's 93 mm (3.7 in), and both months experience similar humidity levels, with May at 78% and September at 75%. For a detailed look at May's weather conditions, check out Mount Vernon weather in May.
In comparing the weather of September and June, both months exhibit similar maximum temperatures, peaking at around 37°C (99°F) in September and 38°C (98°F) in June. However, September presents a slightly broader temperature range, with minimum temperatures dropping to 6°C (44°F) compared to June’s 9°C (49°F). Additionally, September experiences lower average temperatures, averaging 22°C (73°F), while June averages a warmer 24°C (76°F). In terms of precipitation, June sees a touch more, with 107 mm (4.2 in) over 13 days, contrasted with September's 93 mm (3.7 in) over 11 days. The humidity levels are also comparable, with September at 75% and June slightly higher at 79%. For more detailed information about June weather, you can check Mount Vernon weather in June.
In comparing the weather of September and July, September generally experiences a wider temperature range, with minimum temperatures dropping to 6°C (44°F) and maximums reaching up to 37°C (99°F). Average temperatures in September hover around 22°C (73°F), making it feel cooler than July, which has a milder minimum of 16°C (61°F) and a higher average of 27°C (81°F). While July sees slightly more precipitation at 132 mm (5.2 in) over 12 days compared to September's 93 mm (3.7 in) across 11 days, the humidity levels remain quite similar, with September at 75% and July slightly lower at 74%. For a more detailed look at July weather specifics, you can visit Mount Vernon weather in July.
In comparing the weather of September and August, September presents a notable shift in temperature, with a minimum of 6°C compared to August's warmer minimum of 15°C. The average temperature in September is slightly cooler at 22°C (73°F) compared to August's average of 25°C (78°F), yet both months share a maximum temperature peak of 37°C (99°F). Rainfall is another point of distinction; September experiences 93 mm of precipitation over 11 days, while August receives more substantial rainfall at 146 mm across 15 days. Humidity levels remain relatively similar, with September at 75% and August just slightly lower at 72%. For more detailed information, you can check Mount Vernon weather in August.
In September, temperatures typically range from a minimum of 6°C (44°F) to a maximum of 37°C (99°F), providing a warm average of 22°C (73°F). The month experiences about 93 mm (3.7 in) of precipitation over 11 days, with humidity levels at 75%. In contrast, October sees cooler temperatures, with a minimum of 2°C (36°F) and an average of 17°C (63°F), peaking at 36°C (97°F). Rainfall increases slightly to 105 mm (4.2 in) across 9 days, accompanied by higher humidity at 81%. For more specific insights into the weather during this month, you can check Mount Vernon weather in October.
September and November present stark contrasts in weather conditions. September boasts warmer temperatures, with minimums around 6°C (44°F) and maximums peaking at 37°C (99°F), creating an average of 22°C (73°F). The month sees considerable rainfall totaling 93 mm (3.7 in) across 11 days, alongside a humidity level of 75%. In contrast, November experiences a significant drop in temperatures, with minimums dipping to -5°C (23°F) and a much cooler average of 9°C (48°F). Maximums reach 26°C (78°F), and the month features less precipitation, totaling 77 mm (3.0 in) over just 7 days, while humidity rises to 85%. For more detailed weather patterns, check out Mount Vernon weather in November.
September and December present starkly contrasting weather patterns. In September, the temperature ranges from a mild 6°C (44°F) to a scorching 37°C (99°F), with an average of 22°C (73°F) and a considerable amount of humidity at 75%. The month experiences about 93 mm (3.7 in) of precipitation over 11 days. In contrast, December temperatures drop significantly, with a minimum of -10°C (14°F) and a maximum of 20°C (69°F), averaging just 5°C (42°F). Despite slightly lower precipitation at 89 mm (3.5 in) over 9 days, December's humidity rises to 84%, indicating a damp chill in the air. For further details, you can check Mount Vernon weather in December.
September in Mount Vernon brings a delightful transition in weather as the summer heat begins to wane. With milder temperatures and an average that encourages outdoor activities, the month stands apart from the sweltering extremes of July and August. While still experiencing some warmth, September's conditions are a welcome reprieve marked by increased humidity and occasional rainfall, perfect for vibrant autumn foliage and refreshing breezes. As you plan your visit, explore more about the changing seasons and what to expect by checking out Mount Vernon Climate.