September Weather in Sterling, United States

Last updated: June 24, 2025

In September, the average temperature in Sterling, United States hovers around 20°C (68°F), offering a pleasant climate for outdoor activities. However, temperatures can vary significantly, with a minimum of 1°C (34°F) and a maximum soaring to 38°C (102°F). Expect some precipitation with an average of 25 mm (1.0 in) spread across 4 days, adding to the region's average humidity of 75%. Prepare accordingly for both sunny days and refreshing showers!

September Temperature in Sterling

In September in Sterling, the average temperature is 20°C (68°F). Maximums can reach 38°C (102°F) and minimums can be as low as 1°C (34°F). Be prepared for a wide range of temperatures, making it essential to pack both lightweight clothing and warmer layers for your travels.

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

The chart illustrates September temperature patterns in Sterling, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sterling, September typically has an average temperature of 20°C (68°F), with highs reaching up to 38°C (102°F) and lows dropping to around 1°C (34°F).

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

September Precipitation in Sterling

In Sterling in September, the precipitation amount is 25 mm (1.0 in) over the course of 4 days.

September Precipitation Trends in Sterling

The chart displays monthly precipitation patterns in Sterling, 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 Sterling, September typically receives around 25 mm (1.0 inches) of precipitation spread over approximately 4 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 Sterling

In Sterling in September, humidity is 75%. With an average temperature of 20°C (68°F), this humidity feels like a warm, muggy embrace that can leave travelers feeling sticky and exhausted.

September Average Humidity in Sterling

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

In Sterling 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 Sterling.

Maximum UV Index Levels in Sterling for September

The chart shows the monthly maximum UV Index (UVI) for Sterling 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 Sterling typically reaches 9, which falls under the very high exposure category.

Data source: Sterling 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 Sterling Compares to Other Months

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

This table compares monthly weather conditions in Sterling, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	0°C (33°F)	10 mm (0.4 inches)	72%	moderate
February Weather	-1°C (31°F)	16 mm (0.6 inches)	76%	moderate
March Weather	6°C (43°F)	56 mm (2.2 inches)	61%	high
April Weather	10°C (50°F)	52 mm (2.1 inches)	60%	very high
May Weather	15°C (59°F)	105 mm (4.1 inches)	74%	very high
June Weather	22°C (72°F)	42 mm (1.7 inches)	82%	extreme
July Weather	25°C (77°F)	41 mm (1.6 inches)	82%	extreme
August Weather	23°C (74°F)	28 mm (1.1 inches)	84%	very high
September Weather	20°C (68°F)	25 mm (1.0 inches)	75%	very high
October Weather	10°C (50°F)	25 mm (1.0 inches)	73%	high
November Weather	6°C (43°F)	15 mm (0.6 inches)	74%	moderate
December Weather	2°C (35°F)	10 mm (0.4 inches)	77%	moderate