September Weather in Bellingham, United States

Last updated: June 24, 2025

In Bellingham, United States, the average temperature in September hovers around 15°C (60°F), with a minimum of 7°C (46°F) and a comfortable maximum of 27°C (81°F). Expect about 125 mm (4.9 in) of precipitation spread over 11 days, contributing to an average humidity of 76%. Perfect for embracing the seasonal vibe!

September Temperature in Bellingham

In September in Bellingham, the average temperature is 15°C (60°F). Maximums can reach 27°C (81°F), while minimums can drop as low as 7°C (46°F). This makes Bellingham a comfortable destination for travelers looking to enjoy mild weather and a pleasant outdoor experience.

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

The chart illustrates September temperature patterns in Bellingham, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Bellingham, September typically has an average temperature of 15°C (60°F), with highs reaching up to 27°C (81°F) and lows dropping to around 7°C (46°F).

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

September Precipitation in Bellingham

In Bellingham in September, the precipitation amount is 125 mm (4.9 in) over the course of 11 days.

September Precipitation Trends in Bellingham

The chart displays monthly precipitation patterns in Bellingham, 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 Bellingham, September typically receives around 125 mm (4.9 inches) of precipitation spread over approximately 11 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 Bellingham

In Bellingham in September humidity is 76%. With an average temperature of 15°C (60°F), this humidity feels like a warm, damp blanket wrapping around you, making outdoor activities a bit more challenging and urging you to stay hydrated while exploring the area.

September Average Humidity in Bellingham

This chart illustrates the average monthly humidity levels in Bellingham, 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 Bellingham is approximately 76%, 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 Bellingham

In Bellingham in September, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in Bellingham, you can refer to this Hourly UV Index in Bellingham.

Maximum UV Index Levels in Bellingham for September

The chart shows the monthly maximum UV Index (UVI) for Bellingham 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 Bellingham typically reaches 6, which falls under the high exposure category.

Data source: Bellingham 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 Bellingham Compares to Other Months

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

This table compares monthly weather conditions in Bellingham, 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 (41°F)	199 mm (7.8 inches)	86%	low
February Weather	4°C (39°F)	185 mm (7.3 inches)	85%	moderate
March Weather	6°C (44°F)	156 mm (6.2 inches)	86%	moderate
April Weather	9°C (48°F)	127 mm (5.0 inches)	86%	high
May Weather	12°C (53°F)	76 mm (3.0 inches)	81%	very high
June Weather	15°C (59°F)	58 mm (2.3 inches)	83%	very high
July Weather	17°C (63°F)	27 mm (1.1 inches)	84%	very high
August Weather	18°C (64°F)	19 mm (0.8 inches)	77%	very high
September Weather	15°C (60°F)	125 mm (4.9 inches)	76%	high
October Weather	11°C (51°F)	186 mm (7.3 inches)	88%	moderate
November Weather	8°C (46°F)	261 mm (10.3 inches)	87%	low
December Weather	5°C (41°F)	227 mm (8.9 inches)	87%	low