September Weather in Westminster, United States

Last updated: June 24, 2025

In September, the average temperature in Westminster, United States is a comfortable 21°C (70°F), with lows dipping to 5°C (42°F) and highs reaching up to 34°C (93°F). Expect 116 mm (4.5 in) of precipitation spread over 10 days, while the ambience remains humid, with an average humidity of 75%.

September Temperature in Westminster

In September in Westminster, the average temperature is 21°C (70°F), with maximums reaching 34°C (93°F) and minimums dropping as low as 5°C (42°F). This range makes Westminster a perfect destination for travelers seeking both warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Westminster, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Westminster, September typically has an average temperature of 21°C (70°F), with highs reaching up to 34°C (93°F) and lows dropping to around 5°C (42°F).

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

September Precipitation in Westminster

In Westminster in September, the precipitation amount is 116 mm (4.5 in) over the course of 10 days.

September Precipitation Trends in Westminster

The chart displays monthly precipitation patterns in Westminster, 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 Westminster, September typically receives around 116 mm (4.5 inches) of precipitation spread over approximately 10 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 Westminster

In Westminster in September, humidity is 75%. With an average temperature of 21°C (70°F), this humidity feels like a warm, enveloping blanket that makes exploring the area feel slightly sticky, requiring travelers to stay hydrated and take occasional breaks in the shade to fully enjoy their adventures.

September Average Humidity in Westminster

This chart illustrates the average monthly humidity levels in Westminster, 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 Westminster is approximately 75%, 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 Westminster

In Westminster in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Westminster.

Maximum UV Index Levels in Westminster for September

The chart shows the monthly maximum UV Index (UVI) for Westminster 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 Westminster typically reaches 8, which falls under the very high exposure category.

Data source: Westminster 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 Westminster Compares to Other Months

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

This table compares monthly weather conditions in Westminster, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	2°C (35°F)	62 mm (2.4 inches)	84%	moderate
February Weather	4°C (39°F)	95 mm (3.8 inches)	83%	moderate
March Weather	7°C (44°F)	93 mm (3.6 inches)	83%	high
April Weather	12°C (55°F)	95 mm (3.7 inches)	81%	very high
May Weather	18°C (64°F)	144 mm (5.7 inches)	78%	very high
June Weather	23°C (73°F)	125 mm (4.9 inches)	79%	very high
July Weather	26°C (78°F)	152 mm (6.0 inches)	74%	very high
August Weather	24°C (76°F)	156 mm (6.1 inches)	72%	very high
September Weather	21°C (70°F)	116 mm (4.5 inches)	75%	very high
October Weather	15°C (60°F)	103 mm (4.1 inches)	81%	high
November Weather	7°C (45°F)	90 mm (3.6 inches)	85%	moderate
December Weather	4°C (39°F)	96 mm (3.8 inches)	84%	moderate