September Weather in Gillette, United States

Last updated: June 24, 2025

In September, the average temperature in Gillette, United States hovers around 16°C (62°F). However, temperatures can vary significantly, with a minimum of -2°C (30°F) and a maximum reaching up to 38°C (101°F). Expect approximately 43 mm (1.7 in) of precipitation spread over 6 days, coupled with an average humidity of 79%.

September Temperature in Gillette

In September in Gillette, the average temperature is 16°C (62°F). Maximums can reach 38°C (101°F) and minimums can drop as low as -2°C (30°F). Be prepared for a wide range of temperatures, making it essential to pack both warm and cool clothing for your travels.

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

The chart illustrates September temperature patterns in Gillette, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Gillette, September typically has an average temperature of 16°C (62°F), with highs reaching up to 38°C (101°F) and lows dropping to around -2°C (30°F).

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

September Precipitation in Gillette

In Gillette in September, the precipitation amount is 43 mm (1.7 in) over a period of 6 days.

September Precipitation Trends in Gillette

The chart displays monthly precipitation patterns in Gillette, 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 Gillette, September typically receives around 43 mm (1.7 inches) of precipitation spread over approximately 6 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 Gillette

In Gillette in September, humidity is 79%. With an average temperature of 16°C (62°F), this humidity feels like a warm, enveloping blanket that makes walking outdoors feel languid and heavy, demanding frequent breaks and plenty of water as you navigate the bustling streets.

September Average Humidity in Gillette

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

In Gillette 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 Gillette.

Maximum UV Index Levels in Gillette for September

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

Data source: Gillette 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 Gillette Compares to Other Months

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

This table compares monthly weather conditions in Gillette, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-3°C (27°F)	19 mm (0.8 inches)	78%	moderate
February Weather	-5°C (23°F)	26 mm (1.0 inches)	79%	moderate
March Weather	3°C (38°F)	33 mm (1.3 inches)	71%	high
April Weather	6°C (42°F)	61 mm (2.4 inches)	70%	very high
May Weather	12°C (53°F)	67 mm (2.6 inches)	75%	very high
June Weather	19°C (67°F)	39 mm (1.6 inches)	82%	extreme
July Weather	23°C (74°F)	56 mm (2.2 inches)	84%	extreme
August Weather	21°C (71°F)	35 mm (1.4 inches)	85%	very high
September Weather	16°C (62°F)	43 mm (1.7 inches)	79%	very high
October Weather	6°C (44°F)	47 mm (1.9 inches)	75%	moderate
November Weather	3°C (37°F)	20 mm (0.8 inches)	75%	moderate
December Weather	-1°C (30°F)	24 mm (0.9 inches)	81%	low