nomadseason

September Weather in Brentwood, United States

Last updated: June 24, 2025

In September, the average temperature in Brentwood, United States is 23°C (74°F), making it a pleasant time to visit. Expect temperature ranges from a cool 8°C (48°F) to a sweltering 37°C (98°F). Be prepared for 128 mm (5.0 in) of precipitation over approximately 9 days, contributing to an average humidity level of 64%.

September Temperature in Brentwood

In September in Brentwood, the average temperature is 23°C (74°F), with maximums reaching 37°C (98°F) and minimums dropping as low as 8°C (48°F). Be prepared for warm days and cooler nights, ideal for a variety of outdoor activities and explorations.

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

The chart illustrates September temperature patterns in Brentwood, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Brentwood, September typically has an average temperature of 23°C (74°F), with highs reaching up to 37°C (98°F) and lows dropping to around 8°C (48°F).
JanFebMarAprMayJunJulAugSepOctNovDec414553597077807874634845
Data source: Temperature data for Brentwood 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 Brentwood

In Brentwood in September, the precipitation amount is 128 mm (5.0 in) over a span of 9 days.

September Precipitation Trends in Brentwood

The chart displays monthly precipitation patterns in Brentwood, 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 Brentwood, September typically receives around 128 mm (5.0 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec10317917014811614214113312813881151
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Brentwood

In Brentwood in September, humidity is 64%. With an average temperature of 23°C (74°F), this humidity feels like a warm blanket wrapping around you, making outdoor exploration enjoyable yet slightly sticky, so it's best to stay hydrated and take breaks in the shade while traveling.

September Average Humidity in Brentwood

This chart illustrates the average monthly humidity levels in Brentwood, 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 Brentwood is approximately 64%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%85%82%83%82%78%67%64%75%87%89%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Brentwood

In Brentwood in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Brentwood.

Maximum UV Index Levels in Brentwood for September

The chart shows the monthly maximum UV Index (UVI) for Brentwood 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 Brentwood typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
Data source: Brentwood 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 Brentwood Compares to Other Months

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

This table compares monthly weather conditions in Brentwood, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather5°C (41°F)103 mm (4.0 inches)87%moderate
February Weather7°C (45°F)179 mm (7.0 inches)87%high
March Weather11°C (53°F)170 mm (6.7 inches)85%high
April Weather15°C (59°F)148 mm (5.8 inches)82%very high
May Weather21°C (70°F)116 mm (4.6 inches)83%very high
June Weather25°C (77°F)142 mm (5.6 inches)82%extreme
July Weather27°C (80°F)141 mm (5.5 inches)78%extreme
August Weather26°C (78°F)133 mm (5.2 inches)67%very high
September Weather23°C (74°F)128 mm (5.0 inches)64%very high
October Weather17°C (63°F)138 mm (5.4 inches)74%high
November Weather9°C (49°F)81 mm (3.2 inches)87%moderate
December Weather7°C (46°F)150 mm (5.9 inches)88%moderate

Compare Brentwood's Climate with Cities Worldwide