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September Weather in Arlington, United States

Last updated: June 24, 2025

In Arlington, United States, the average temperature in September is a comfortable 21°C (69°F). While the mercury can dip to a chilly 5°C (41°F), it can also soar to a scorching 36°C (98°F). Expect 79 mm (3.1 in) of precipitation over 9 days, contributing to an average humidity of 75% that keeps the air feeling fresh.

September Temperature in Arlington

In September in Arlington, the average temperature is 21°C (69°F). Maximum temperatures can reach 36°C (98°F), while the minimum can dip to as low as 5°C (41°F). This diverse temperature range makes Arlington an ideal destination for travelers seeking both warm and cooler experiences.

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. In Arlington, September typically has an average temperature of 21°C (69°F), with highs reaching up to 36°C (98°F) and lows dropping to around 5°C (41°F).
JanFebMarAprMayJunJulAugSepOctNovDec252541506275787469523931
Data source: Temperature data for Arlington generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Arlington

In Arlington in September, the precipitation amount is 79 mm (3.1 in) spread over 9 days.

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. In Arlington, September typically receives around 79 mm (3.1 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec3230925915212368103791053041
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Arlington

In Arlington in September, humidity is 75%. With an average temperature of 21°C (69°F), this humidity feels like a warm, sticky embrace that can make even a short walk feel exhausting for travelers, often leading to a longing for refreshing breezes or air-conditioned retreats.

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, helping you understand how conditions vary by season. In September, average humidity in Arlington is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%80%73%75%78%82%83%81%75%75%82%83%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Arlington

In Arlington in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Arlington.

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. In September, the maximum UV index in Arlington typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098642
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.

How September Weather in Arlington Compares to Other Months

Weather in Arlington varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Arlington, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Arlington, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)32 mm (1.2 inches)76%moderate
February Weather-4°C (25°F)30 mm (1.2 inches)80%moderate
March Weather5°C (41°F)92 mm (3.6 inches)73%high
April Weather10°C (50°F)59 mm (2.3 inches)74%very high
May Weather17°C (63°F)151 mm (6.0 inches)78%very high
June Weather24°C (76°F)123 mm (4.8 inches)82%very high
July Weather25°C (78°F)68 mm (2.7 inches)83%very high
August Weather23°C (74°F)103 mm (4.1 inches)80%very high
September Weather21°C (69°F)79 mm (3.1 inches)75%very high
October Weather11°C (53°F)105 mm (4.1 inches)75%high
November Weather4°C (40°F)30 mm (1.2 inches)82%moderate
December Weather-1°C (31°F)41 mm (1.6 inches)83%low

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