September Weather in Arlington, United States

Last updated: February 24, 2025

September in Arlington, United States, showcases a dynamic range of weather, with maximum temperatures soaring to 36°C (97°F), while average conditions hover around a comfortable 22°C (72°F). The month also presents cooler days, with temperatures dipping to a brisk 5°C (42°F). Rainfall is a frequent visitor, contributing 95 mm (3.8 in) over 11 days, accompanied by a notable humidity level of 75%. This blend of warmth, occasional precipitation, and moisture creates an engaging atmosphere, ideal for enjoying the fading summer and transitioning into autumn.

September Temperature in Arlington

September in Arlington ushers in a delightful transition from summer’s heat, characterized by temperatures that range from a minimum of 5°C (42°F) to a maximum of 36°C (97°F). The average temperature settles at a comfortable 22°C (72°F), offering a pleasant reprieve for outdoor activities. As the month progresses, the warmth begins to diminish, hinting at the cooler days ahead. This shift not only marks a change in weather but also in lifestyle, as residents embrace the crispness of autumn. September's temperatures reflect a blend of lingering summer warmth and the early signs of fall, making it a vibrant and dynamic month in Arlington.

September Weather in Arlington: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Arlington, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec374146566675807772624740
Data source: Temperature data for Arlington generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Arlington

September sees precipitation in Arlington, United States, amounting to an average of 95 mm (3.8 in) over 11 days. This marks a slight decrease from the wetter months of July and August, where the rainfall peaked at 157 mm (6.2 in) and 140 mm (5.5 in), respectively. As summer gives way to autumn, September’s rainfall hints at the changing seasons, with moisture levels transitioning closer to those seen in April and October. This gradual shift signifies a trend towards lighter, more sporadic showers that invite the crispness of fall, providing a refreshing break from the intense summer heat. The relatively moderate precipitation also suggests a balance, as Arlington prepares for the drier days ahead.

September Precipitation Trends in Arlington

The chart displays monthly precipitation patterns in Arlington, with values for each month alongside September's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec619887100127118157140951058193
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Arlington

September ushers in a gentle shift in humidity levels in Arlington, United States, recording 75% humidity—slightly higher than the preceding summer months, which saw lows around 72% in August and 74% in July. This subtle uptick reflects the onset of autumn, characterized by a gradual increase as the warmth of summer recedes. As the city transitions into fall, humidity levels begin to creep back up, setting the stage for the wetter months ahead, particularly October, which typically sees a rise to 81%. This trend illustrates Arlington's unique climate rhythm, where the summer heat gives way to a refreshing, yet still humid, autumn atmosphere.

September Average Humidity in Arlington

This chart illustrates the average monthly humidity levels in Arlington, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec84%83%83%81%78%79%74%72%75%81%85%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Arlington

As September rolls into Arlington, the UV Index remains notably high at 8, signaling that this month still demands caution when spending time outdoors. With a burn time of just 15 minutes, sun exposure is critical, tapering slightly from the peak summer months but still classified as very high. This trend indicates a gradual decline from the intense UV rays experienced in July and August, where the Index reached its annual maximum of 10. As we transition into fall, the UV Index will continue to decrease, but for now, residents should stay vigilant. To learn more about daily UV levels, check out Arlington UV Index.

Maximum UV Index Levels in Arlington for September

The chart shows the monthly maximum UV Index (UVI) for Arlington in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec357910101098753
Data source: Arlington September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Arlington

September in Arlington shines with an impressive 277 hours of sunshine, marking a beautiful transition from the intense brightness of summer. As the days grow shorter, the sun continues to bless the region with a significant amount of light, following a peak of 356 hours in July. The month stands out as a vibrant time, nestled comfortably between the lush summer months and the cooler autumn days, capturing a lingering warmth that invites outdoor activities. Although there's a slight decrease compared to the summer highs, September maintains a commendable brightness, ensuring that residents can enjoy those soft, sunlit afternoons before the fall truly settles in. Overall, the trend reveals a steady abundance of sunshine, especially in the warmer months, creating a delightful atmosphere for both locals and visitors alike.

Monthly Sunshine Duration in Arlington: September Highlighted

The September sunshine duration represents the total number of hours Arlington experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec150h180h259h259h281h330h356h321h277h246h226h191h
Data source: Arlington September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Arlington During September

In Arlington, the likelihood of sunny weather peaks in September, with an impressive 53% chance of sunshine compared to other months of the year. This marks a notable shift from the summer months, where the chances dwindle, with July and August seeing only 49% and 34%, respectively. As the heat of summer recedes, September offers a refreshing transition, presenting clearer skies more frequently. Interestingly, this month also leads into the fall, where sunshine opportunities begin to fluctuate, with October dropping to 39%. Overall, September stands out as a bright spot in Arlington’s weather calendar, inviting residents and visitors to embrace the delightful warmth and sunshine before the chill of autumn sets in.

Percentage of Sunny Days in September in Arlington

The chart illustrates the percentage of sunny days in Arlington throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Arlington experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec45%28%53%48%40%38%49%34%53%40%56%37%
Data source: Arlington September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Arlington in September

As summer bids farewell in September, Arlington enjoys a gentle transition from the abundant 14 hours of daylight seen in July and June to a more moderate 12 hours. This gradual decrease signals the onset of autumn, where daylight begins to wane. Following the trend of longer days in spring, which peak in May and June, September subtly shifts the focus towards shorter daylight periods as October approaches with its 11 hours. The rhythm of the seasons is evident here, as nature prepares for the cozy embrace of fall, inviting residents to savor the crisp, sunlit days that herald the change in weather.

Average Daylight Hours in Arlington for September

The chart illustrates the variation in daylight duration in Arlington throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 46m10h 44m11h 58m13h 14m14h 18m14h 50m14h 32m13h 36m12h 23m11h 7m10h 1m9h 28m
Data source: Arlington daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Arlington

As September arrives in Arlington, the transition into fall brings a gentle increase in wind speed, averaging 2.6 m/s (6 mph). This modest uptick from the summer lows marks a departure from the 1.9 m/s (4 mph) experienced in August. The gradual shift in wind patterns highlights a consistent seasonal rhythm, where the winds typically pick up after the sultry summer months, reflecting nature's preparation for the cooler days ahead. With the breeze becoming more noticeable, September offers a refreshing backdrop for outdoor activities, making it a delightful time to enjoy the changing landscape. As autumn unfolds, wind speeds will continue to oscillate, yet September sets the stage with its inviting gusts, heralding the beauty of the season.

Average September Wind Speed in Arlington

The chart displays monthly wind speed patterns in Arlington, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.03.23.33.32.82.52.21.92.6 m/s2.82.92.8
Data source: Arlington September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Arlington Compares to Other Months

The weather in Arlington 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 Arlington and find detailed weather information for every month.

In September, temperatures in Arlington range from a mild 5°C (42°F) at night to a warm 36°C (97°F) during the day, with an average temperature of 22°C (72°F). The month experiences significant humidity at 75%, coupled with 95 mm (3.8 in) of precipitation spread over 11 days, indicating a transition towards fall.

In contrast, January brings a stark change in climate, where temperatures drop dramatically, ranging from a frigid -15°C (5°F) to a daytime high of 22°C (71°F), with an average of only 3°C (37°F). Despite the colder temperatures, January sees less total precipitation at 61 mm (2.4 in) over 8 days, and the humidity rises slightly to 84%. For more details about January weather in Arlington, visit Arlington weather in January.

September and February present starkly contrasting weather conditions. In September, temperatures range from a mild 5°C (42°F) at night to soaring highs of 36°C (97°F) during the day, with an average of 22°C (72°F). The month experiences about 95 mm (3.8 inches) of precipitation over 11 days, coupled with a humidity level of 75%. In contrast, February brings much colder temperatures, with lows plummeting to -16°C (4°F) and daytime highs reaching only 28°C (82°F), making the average a chilly 5°C (41°F). Precipitation is slightly higher at 98 mm (3.9 inches) over the same number of days, and humidity also increases to 83%. For more details, you can visit Arlington weather in February.

September and March offer distinct weather profiles, highlighting the transition between summer and winter. In September, temperatures range from a minimum of 5°C (42°F) to a maximum of 36°C (97°F), creating warm days with an average of 22°C (72°F). However, it also experiences notable humidity at 75% and higher precipitation, totaling 95 mm (3.8 in) over 11 days. In contrast, March experiences cooler temperatures, with a minimum of -7°C (20°F) and a maximum of 28°C (83°F), resulting in an average of just 8°C (46°F). While March has slightly lower precipitation at 87 mm (3.4 in) over 10 days, it also sees higher humidity at 83%. To explore more about March weather in detail, you can check Arlington weather in March.

When comparing the weather in September and April, one can observe notable differences in temperature and humidity levels. September boasts warmer temperatures, with an average of 22°C (72°F) and a maximum of 36°C (97°F), making it significantly hotter than April, which has an average temperature of 14°C (57°F) and a maximum of 32°C (91°F). Both months experience similar precipitation levels, with September receiving 95 mm (3.8 in) and April slightly higher at 100 mm (4.0 in), each spanning approximately 11 days of rain. However, September has a lower humidity rate of 75% compared to April's 81%, resulting in a more comfortable atmosphere in the earlier fall month. For detailed insights into April's weather, you can check Arlington weather in April.

In comparing the weather of September and May, we see distinct differences in temperature and precipitation. September tends to have warmer temperatures, with averages reaching up to 22°C (72°F) and maximums hitting 36°C (97°F). In contrast, May has slightly cooler temperatures, averaging around 19°C (66°F) and peaking at 34°C (94°F). When it comes to rainfall, May is wetter, receiving 127 mm (5.0 in) over 13 days, compared to September's 95 mm (3.8 in) over 11 days. Notably, humidity levels remain high in both months, with September at 75% and May at 78%. For more detailed insights, check out Arlington weather in May.

When comparing the weather in September and June, both months exhibit the potential for high temperatures, with maximums reaching up to 36°C (97°F) in September and 36°C (98°F) in June. However, September tends to have a slightly lower average minimum temperature of 5°C (42°F) compared to June's 9°C (48°F). On the precipitation front, June is wetter, receiving 118 mm (4.7 in) compared to September's 95 mm (3.8 in), with rain occurring on about 12 days in June versus 11 days in September. Additionally, humidity levels are comparable, with September at 75% and June slightly higher at 79%. For a more detailed look at June's weather, you can visit Arlington weather in June.

When comparing the weather in September and July, notable differences emerge. September experiences a broader temperature range, with minimums dropping to 5°C (42°F) and maximums reaching up to 36°C (97°F), resulting in an average temperature of 22°C (72°F). In contrast, July has milder minimum temperatures of 15°C (59°F) and warmer maximums averaging 38°C (101°F), leading to a higher average of 27°C (81°F). Precipitation is also notably different; September sees 95 mm (3.8 in) spread over 11 days, while July receives 157 mm (6.2 in) over 12 days, indicating a wetter month. Humidity remains fairly consistent, with September at 75% and July slightly lower at 74%. For more specifics, you can explore Arlington weather in July.

In August, temperatures were generally warmer, with a minimum of 14°C (58°F) and an average of 25°C (77°F), peaking at a high of 37°C (99°F). The month also experienced more rainfall, totaling 140 mm (5.5 in) over 15 days, accompanied by slightly lower humidity at 72%. In contrast, September saw a drop in temperatures, with a minimum of 5°C (42°F) and an average of 22°C (72°F), reaching a maximum of 36°C (97°F). Although it was still warm, September was slightly drier, recording 95 mm (3.8 in) of precipitation over 11 days and maintaining a higher humidity level of 75%. For more detailed information on August weather, check Arlington weather in August.

September and October exhibit notable differences in weather patterns. September tends to be warmer, with average temperatures around 22°C (72°F) and maximums reaching up to 36°C (97°F). In contrast, October sees a drop in average temperatures to 17°C (62°F), with a minimum of 1°C (34°F). While both months experience similar maximum temperatures, precipitation increases slightly in October to 104 mm (4.1 in), although it falls over just 9 days compared to 11 days in September. Additionally, October's humidity rises to 81%, making the air feel a bit more oppressive. For more detailed information, you can check out Arlington weather in October.

September and November present contrasting weather conditions. In September, temperatures range from a minimum of 5°C (42°F) to a maximum of 36°C (97°F), with an average of 22°C (72°F). This month typically experiences 95 mm (3.8 in) of precipitation over 11 days, alongside a humidity level of 75%. In contrast, November sees significantly cooler temperatures, with a minimum of -6°C (21°F) and a maximum of 25°C (78°F), averaging just 8°C (47°F). This month receives slightly less precipitation at 81 mm (3.2 in) across 7 days, although humidity levels increase to 85%. For more detailed information on November's weather, you can visit Arlington weather in November.

September and December showcase contrasting weather patterns. September tends to be warm, with average temperatures around 22°C (72°F) and maximums reaching up to 36°C (97°F), while experiencing significant humidity at 75% and 95 mm of precipitation over 11 days. In stark contrast, December brings much cooler conditions, with average temperatures dropping to 5°C (41°F) and a maximum of 20°C (69°F). Precipitation remains relatively stable at 93 mm over 9 days, but the humidity increases to 84%, creating a noticeably crisp atmosphere. For more details about the weather in December, check out Arlington weather in December.

Compare Arlington's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Arlington

As September arrives in Arlington, a noticeable shift in weather sets the stage for a transitional month. While summer's warmth may linger with temperatures reaching the heights of 36°C, the average cools down to a more comfortable 22°C, providing a welcome respite from the sweltering summer heat. With 95 mm of precipitation spread over 11 days, the month showcases a characteristic increase in humidity at 75%, hinting at the forthcoming fall season. This blend of warmth and moisture creates an inviting atmosphere, making September a unique time to experience Arlington’s changing climate. For more detailed insights, check out the full Arlington Climate.