September Weather in Thornton, United States

Last updated: June 24, 2025

In Thornton, United States during September, the average temperature hovers around 23°C (73°F). However, temperatures can experience a wide range, dipping as low as 9°C (48°F) and soaring to a scorching 42°C (108°F). Rainfall is minimal, with an average precipitation of just 1 mm (0.0 in) over 0 days. To complement the warmth, the average humidity stands at a comfortable 44%.

September Temperature in Thornton

In September in Thornton, the average temperature is 23°C (73°F). Maximum can reach 42°C (108°F) and minimum can be as low as 9°C (48°F). Be prepared for a wide range of temperatures when traveling during this month, as both heat and cool conditions can occur.

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

The chart illustrates September temperature patterns in Thornton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Thornton, September typically has an average temperature of 23°C (73°F), with highs reaching up to 42°C (108°F) and lows dropping to around 9°C (48°F).

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

September Precipitation in Thornton

In Thornton in September, the precipitation amount is 1 mm (0.0 in) during a span of 0 days.

September Precipitation Trends in Thornton

The chart displays monthly precipitation patterns in Thornton, 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 Thornton, September typically receives around 1 mm (0.0 inches) of precipitation spread over approximately 0 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 Thornton

In Thornton in September humidity is 44%. With an average temperature of 23°C (73°F), this humidity feels like a pleasant embrace, making it comfortable for travelers to explore and enjoy outdoor activities without feeling too sticky or overheated.

September Average Humidity in Thornton

This chart illustrates the average monthly humidity levels in Thornton, 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 Thornton is approximately 44%, 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 Thornton

In Thornton 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 Thornton.

Maximum UV Index Levels in Thornton for September

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

Data source: Thornton 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 Thornton Compares to Other Months

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

This table compares monthly weather conditions in Thornton, 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)	116 mm (4.6 inches)	84%	moderate
February Weather	12°C (53°F)	100 mm (3.9 inches)	84%	moderate
March Weather	14°C (57°F)	83 mm (3.3 inches)	83%	high
April Weather	17°C (63°F)	39 mm (1.5 inches)	81%	very high
May Weather	20°C (68°F)	17 mm (0.7 inches)	74%	very high
June Weather	23°C (74°F)	2 mm (0.1 inches)	64%	extreme
July Weather	24°C (75°F)	0 mm (0.0 inches)	44%	extreme
August Weather	24°C (75°F)	0 mm (0.0 inches)	36%	very high
September Weather	23°C (73°F)	1 mm (0.0 inches)	44%	very high
October Weather	19°C (66°F)	36 mm (1.4 inches)	65%	high
November Weather	13°C (56°F)	46 mm (1.8 inches)	84%	moderate
December Weather	10°C (50°F)	95 mm (3.7 inches)	83%	moderate