September Weather in Brinnon, United States

Last updated: June 24, 2025

In September, the average temperature in Brinnon, United States is a pleasant 14°C (58°F). Expect a range with minimums dipping to 4°C (39°F) and maximums soaring to 28°C (82°F). During this month, you'll likely encounter 114 mm (4.5 in) of precipitation spread over 15 days, contributing to an average humidity of 74%.

September Temperature in Brinnon

In September in Brinnon, the average temperature is 14°C (58°F). The maximum can reach 28°C (82°F) and the minimum can be as low as 4°C (39°F). It's a great time to visit, as you can enjoy mild days and cool nights perfect for exploring.

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

The chart illustrates September temperature patterns in Brinnon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Brinnon, September typically has an average temperature of 14°C (58°F), with highs reaching up to 28°C (82°F) and lows dropping to around 4°C (39°F).

Data source: Temperature data for Brinnon generated using information from the Copernicus Climate Change Service.

September Precipitation in Brinnon

In Brinnon in September, the precipitation amount is 114 mm (4.5 in) spread over a duration of 15 days.

September Precipitation Trends in Brinnon

The chart displays monthly precipitation patterns in Brinnon, 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 Brinnon, September typically receives around 114 mm (4.5 inches) of precipitation spread over approximately 15 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Brinnon

In Brinnon in September humidity is 74%. With an average temperature of 14°C (58°F), this humidity feels like a thick blanket wrapping around you, making outdoor activities slightly uncomfortable and prompting travelers to seek shade or indoor venues more often.

September Average Humidity in Brinnon

This chart illustrates the average monthly humidity levels in Brinnon, 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 Brinnon is approximately 74%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Brinnon

In Brinnon in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Brinnon.

Maximum UV Index Levels in Brinnon for September

The chart shows the monthly maximum UV Index (UVI) for Brinnon 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 Brinnon typically reaches 7, which falls under the high exposure category.

Data source: Brinnon 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 Brinnon Compares to Other Months

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

This table compares monthly weather conditions in Brinnon, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	3°C (38°F)	203 mm (8.0 inches)	86%	low
February Weather	2°C (36°F)	153 mm (6.0 inches)	84%	moderate
March Weather	4°C (39°F)	132 mm (5.2 inches)	85%	moderate
April Weather	7°C (44°F)	118 mm (4.7 inches)	83%	high
May Weather	11°C (52°F)	94 mm (3.7 inches)	84%	very high
June Weather	14°C (57°F)	105 mm (4.1 inches)	84%	very high
July Weather	17°C (63°F)	45 mm (1.8 inches)	82%	very high
August Weather	18°C (64°F)	40 mm (1.6 inches)	73%	very high
September Weather	14°C (58°F)	114 mm (4.5 inches)	74%	high
October Weather	9°C (48°F)	155 mm (6.1 inches)	83%	moderate
November Weather	6°C (42°F)	206 mm (8.1 inches)	86%	moderate
December Weather	3°C (37°F)	207 mm (8.1 inches)	87%	low