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September Weather in Arlington, United States

Last updated: June 24, 2025

In September, the average temperature in Arlington, United States hovers around 18°C (64°F). Be prepared for a range of temperatures, with minimums dropping to 3°C (37°F) and maximums soaring to 33°C (91°F). Expect 98 mm (3.8 in) of precipitation spread over approximately 9 days, contributing to an average humidity of 82%.

September Temperature in Arlington

In September in Arlington, the average temperature is 18°C (64°F), with maximums reaching 33°C (91°F) and minimums dropping as low as 3°C (37°F). Travelers should be prepared for a wide range of temperatures, making layering an essential strategy for comfort during their visit.

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 18°C (64°F), with highs reaching up to 33°C (91°F) and lows dropping to around 3°C (37°F).
JanFebMarAprMayJunJulAugSepOctNovDec171632425771747064473425
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 98 mm (3.8 in) occurring over the course of 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 98 mm (3.8 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec20205975947410210698752532
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 82%. With an average temperature of 18°C (64°F), this humidity feels like a warm, muggy embrace that can make exploring the area feel stifling, leaving travelers drenched in sweat and longing for respite in the shade.

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 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%89%81%82%76%81%82%83%82%82%87%84%
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.
JanFebMarAprMayJunJulAugSepOctNovDec35589101098532
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-8°C (17°F)20 mm (0.8 inches)85%moderate
February Weather-9°C (17°F)20 mm (0.8 inches)89%moderate
March Weather0°C (33°F)59 mm (2.3 inches)81%moderate
April Weather6°C (42°F)75 mm (2.9 inches)82%very high
May Weather14°C (57°F)93 mm (3.7 inches)76%very high
June Weather22°C (71°F)74 mm (2.9 inches)81%very high
July Weather23°C (74°F)102 mm (4.0 inches)82%very high
August Weather21°C (71°F)106 mm (4.2 inches)83%very high
September Weather18°C (64°F)98 mm (3.8 inches)82%very high
October Weather8°C (47°F)75 mm (2.9 inches)82%moderate
November Weather1°C (34°F)25 mm (1.0 inches)87%moderate
December Weather-4°C (25°F)32 mm (1.3 inches)84%low

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