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September Weather in Brightwood, United States

Last updated: June 24, 2025

In Brightwood, United States, the average temperature in September hovers around 21°C (70°F). Expect a range that can dip to a cool 4°C (39°F) or soar to a scorching 35°C (96°F). During this month, you're likely to encounter about 107 mm (4.2 in) of precipitation over approximately 10 days, accompanied by an average humidity level of 68%.

September Temperature in Brightwood

In September in Brightwood, the average temperature is 21°C (70°F), with maximums reaching up to 35°C (96°F) and minimums dropping as low as 4°C (39°F). This makes Brightwood an ideal destination for travelers seeking a mix of warm weather and cooler evenings.

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

The chart illustrates September temperature patterns in Brightwood, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Brightwood, September typically has an average temperature of 21°C (70°F), with highs reaching up to 35°C (96°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec354046566573787570604539
Data source: Temperature data for Brightwood 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 Brightwood

In Brightwood in September, the precipitation amount is 107 mm (4.2 in) accumulated over a period of 10 days.

September Precipitation Trends in Brightwood

The chart displays monthly precipitation patterns in Brightwood, 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 Brightwood, September typically receives around 107 mm (4.2 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec619074112122125921391071098285
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Brightwood

In Brightwood in September humidity is 68%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace, making the air feel slightly heavy and sticky, which can be quite exhausting for travelers.

September Average Humidity in Brightwood

This chart illustrates the average monthly humidity levels in Brightwood, 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 Brightwood is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%84%78%79%70%59%68%80%87%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Brightwood

In Brightwood 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 Brightwood.

Maximum UV Index Levels in Brightwood for September

The chart shows the monthly maximum UV Index (UVI) for Brightwood 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 Brightwood typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3579111010108753
Data source: Brightwood 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 Brightwood Compares to Other Months

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

This table compares monthly weather conditions in Brightwood, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather2°C (36°F)61 mm (2.4 inches)86%moderate
February Weather5°C (41°F)90 mm (3.5 inches)86%moderate
March Weather8°C (46°F)74 mm (2.9 inches)86%high
April Weather13°C (56°F)112 mm (4.4 inches)84%very high
May Weather18°C (65°F)122 mm (4.8 inches)78%extreme
June Weather23°C (73°F)125 mm (4.9 inches)79%very high
July Weather26°C (79°F)92 mm (3.6 inches)70%very high
August Weather24°C (76°F)139 mm (5.5 inches)59%very high
September Weather21°C (70°F)107 mm (4.2 inches)68%very high
October Weather16°C (60°F)109 mm (4.3 inches)80%high
November Weather7°C (45°F)82 mm (3.2 inches)86%moderate
December Weather4°C (40°F)85 mm (3.4 inches)85%moderate

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