September Weather in Kirkland, United States

Last updated: June 24, 2025

In September, the average temperature in Kirkland, United States is a pleasant 25°C (77°F). Expect a minimum of 15°C (59°F) and a maximum that can reach up to 32°C (90°F). Keep in mind that this month brings an average precipitation of 237 mm (9.3 in) over about 13 days, accompanied by a high humidity level of 79%. Prepare accordingly for a mix of warmth and occasional showers!

September Temperature in Kirkland

In September in Kirkland, the average temperature is 25°C (77°F). Maximum can reach 32°C (90°F) and minimum can be as low as 15°C (59°F). This pleasant weather makes it an ideal destination for travelers looking to enjoy outdoor activities and explore the local attractions.

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 25°C (77°F), with highs reaching up to 32°C (90°F) and lows dropping to around 15°C (59°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 reaches 237 mm (9.3 in) over the course of 13 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 237 mm (9.3 inches) of precipitation spread over approximately 13 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 Kirkland

In Kirkland in September, humidity is 79%. With an average temperature of 25°C (77°F), this humidity feels like a warm blanket wrapping around you, making travel feel slightly sluggish but pleasantly tropical.

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 79%, 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 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 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 9, which falls under the very 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	10°C (50°F)	76 mm (3.0 inches)	85%	moderate
February Weather	12°C (53°F)	118 mm (4.6 inches)	82%	high
March Weather	13°C (56°F)	78 mm (3.1 inches)	81%	very high
April Weather	17°C (64°F)	106 mm (4.2 inches)	80%	very high
May Weather	22°C (71°F)	102 mm (4.0 inches)	81%	extreme
June Weather	25°C (77°F)	136 mm (5.4 inches)	81%	extreme
July Weather	27°C (80°F)	151 mm (5.9 inches)	81%	extreme
August Weather	27°C (80°F)	187 mm (7.4 inches)	80%	very high
September Weather	25°C (77°F)	237 mm (9.3 inches)	79%	very high
October Weather	22°C (71°F)	70 mm (2.8 inches)	80%	very high
November Weather	15°C (59°F)	117 mm (4.6 inches)	85%	high
December Weather	12°C (54°F)	138 mm (5.4 inches)	86%	moderate