September Weather in Kirkland, United States

Last updated: June 24, 2025

In Kirkland, United States, the average temperature in September hovers around 16°C (61°F), making it a comfortable time to visit. Expect a minimum chill of 8°C (47°F) and a pleasant maximum of 29°C (85°F). Throughout the month, anticipate approximately 99 mm (3.9 in) of precipitation spread across about 12 days, contributing to an average humidity level of 62%.

September Temperature in Kirkland

In September in Kirkland, the average temperature is 16°C (61°F). Maximums can reach 29°C (85°F) and minimums can be as low as 8°C (47°F). This mild climate makes it an ideal destination for outdoor activities and sightseeing.

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

The chart illustrates September temperature patterns in Kirkland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Kirkland, September typically has an average temperature of 16°C (61°F), with highs reaching up to 29°C (85°F) and lows dropping to around 8°C (47°F).

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

September Precipitation in Kirkland

In Kirkland in September, the total precipitation amount is 99 mm (3.9 in) recorded over a span of 12 days.

September Precipitation Trends in Kirkland

The chart displays monthly precipitation patterns in Kirkland, 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 Kirkland, September typically receives around 99 mm (3.9 inches) of precipitation spread over approximately 12 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 Kirkland

In Kirkland in September, humidity is 62%. With an average temperature of 16°C (61°F), this humidity feels like a gentle blanket, making traveling comfortable yet occasionally sticky, prompting the need for light, breathable clothing to fully enjoy the sights.

September Average Humidity in Kirkland

This chart illustrates the average monthly humidity levels in Kirkland, 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 Kirkland is approximately 62%, 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 Kirkland

In Kirkland 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 Kirkland.

Maximum UV Index Levels in Kirkland for September

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

Data source: Kirkland 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 Kirkland Compares to Other Months

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

This table compares monthly weather conditions in Kirkland, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	6°C (43°F)	178 mm (7.0 inches)	86%	low
February Weather	5°C (41°F)	177 mm (7.0 inches)	86%	moderate
March Weather	7°C (45°F)	128 mm (5.0 inches)	87%	moderate
April Weather	10°C (50°F)	117 mm (4.6 inches)	84%	high
May Weather	13°C (56°F)	77 mm (3.0 inches)	81%	very high
June Weather	16°C (61°F)	73 mm (2.9 inches)	82%	very high
July Weather	18°C (65°F)	27 mm (1.1 inches)	79%	very high
August Weather	19°C (66°F)	24 mm (0.9 inches)	63%	very high
September Weather	16°C (61°F)	99 mm (3.9 inches)	62%	high
October Weather	11°C (52°F)	163 mm (6.4 inches)	83%	moderate
November Weather	8°C (47°F)	188 mm (7.4 inches)	89%	low
December Weather	6°C (42°F)	199 mm (7.8 inches)	88%	low