September Weather in Tumwater, United States

Last updated: June 24, 2025

In September, the average temperature in Tumwater, United States is a pleasant 16°C (61°F), with a minimum dipping to 6°C (43°F) and a maximum peaking at 31°C (88°F). Prepare for some rain, as 88 mm (3.5 in) of precipitation is expected over approximately 10 days, and the air will carry an average humidity of 74%, making it a perfect time for cozy indoor activities or exploring the lush surroundings!

September Temperature in Tumwater

In September in Tumwater, the average temperature is 16°C (61°F). Maximum temperatures can reach 31°C (88°F), while minimums can drop to as low as 6°C (43°F). This range makes it an ideal time for travelers to enjoy a variety of outdoor activities, so be sure to pack accordingly!

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

The chart illustrates September temperature patterns in Tumwater, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Tumwater, September typically has an average temperature of 16°C (61°F), with highs reaching up to 31°C (88°F) and lows dropping to around 6°C (43°F).

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

September Precipitation in Tumwater

In Tumwater in September, the precipitation amount is 88 mm (3.5 in) spread over a duration of 10 days.

September Precipitation Trends in Tumwater

The chart displays monthly precipitation patterns in Tumwater, 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 Tumwater, September typically receives around 88 mm (3.5 inches) of precipitation spread over approximately 10 days.

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

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Millimeters (mm) Inches (in)

September Humidity in Tumwater

In Tumwater in September humidity is 74%. With an average temperature of 16°C (61°F), this humidity feels like a damp blanket wrapping around you, making traveling quite uncomfortable as the air feels thick and muggy, potentially leading to fatigue and a longing for a cool breeze.

September Average Humidity in Tumwater

This chart illustrates the average monthly humidity levels in Tumwater, 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 Tumwater 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 Tumwater

In Tumwater 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 Tumwater.

Maximum UV Index Levels in Tumwater for September

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

Data source: Tumwater 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 Tumwater Compares to Other Months

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

This table compares monthly weather conditions in Tumwater, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	5°C (42°F)	197 mm (7.8 inches)	86%	low
February Weather	5°C (41°F)	155 mm (6.1 inches)	84%	moderate
March Weather	7°C (45°F)	134 mm (5.3 inches)	85%	moderate
April Weather	10°C (50°F)	117 mm (4.6 inches)	83%	high
May Weather	13°C (56°F)	65 mm (2.6 inches)	84%	very high
June Weather	16°C (61°F)	51 mm (2.0 inches)	84%	very high
July Weather	18°C (65°F)	9 mm (0.4 inches)	82%	very high
August Weather	19°C (66°F)	12 mm (0.5 inches)	73%	very high
September Weather	16°C (61°F)	88 mm (3.5 inches)	74%	high
October Weather	11°C (52°F)	133 mm (5.3 inches)	83%	moderate
November Weather	8°C (46°F)	192 mm (7.5 inches)	86%	moderate
December Weather	5°C (42°F)	203 mm (8.0 inches)	87%	low