September Weather in Union, United States

Last updated: June 24, 2025

In September, the average temperature in Union, United States is a warm 26°C (80°F), with minimums dipping to 14°C (58°F) and maximums reaching up to 35°C (96°F). Expect an average precipitation of 166 mm (6.5 in) spread across 16 days, accompanied by an average humidity of 79%. Ideal conditions for experiencing the vibrant atmosphere of this locale!

September Temperature in Union

In September in Union, the average temperature is 26°C (80°F). Maximums can reach 35°C (96°F) and minimums can be as low as 14°C (58°F). This makes Union an ideal destination for travelers seeking warm weather while also enjoying cooler evenings.

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

The chart illustrates September temperature patterns in Union, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Union, September typically has an average temperature of 26°C (80°F), with highs reaching up to 35°C (96°F) and lows dropping to around 14°C (58°F).

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

September Precipitation in Union

In Union in September, the total precipitation amount is 166 mm (6.5 in) spread over 16 days.

September Precipitation Trends in Union

The chart displays monthly precipitation patterns in Union, 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 Union, September typically receives around 166 mm (6.5 inches) of precipitation spread over approximately 16 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 Union

In Union in September, humidity is 79%. With an average temperature of 26°C (80°F), this humidity feels like an enveloping warm blanket, making travel feel slightly sluggish and prompting frequent hydration breaks to stay comfortable while exploring the sights.

September Average Humidity in Union

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

In Union in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Union.

Maximum UV Index Levels in Union for September

The chart shows the monthly maximum UV Index (UVI) for Union 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 Union typically reaches 11, which falls under the extreme exposure category.

Data source: Union 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 Union Compares to Other Months

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

This table compares monthly weather conditions in Union, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	12°C (54°F)	95 mm (3.8 inches)	81%	moderate
February Weather	15°C (60°F)	112 mm (4.4 inches)	81%	very high
March Weather	18°C (65°F)	69 mm (2.7 inches)	79%	very high
April Weather	21°C (69°F)	118 mm (4.6 inches)	81%	extreme
May Weather	25°C (77°F)	138 mm (5.4 inches)	77%	extreme
June Weather	27°C (81°F)	207 mm (8.2 inches)	74%	extreme
July Weather	28°C (82°F)	220 mm (8.7 inches)	74%	extreme
August Weather	28°C (82°F)	220 mm (8.7 inches)	73%	extreme
September Weather	26°C (80°F)	166 mm (6.5 inches)	79%	extreme
October Weather	23°C (73°F)	118 mm (4.6 inches)	77%	very high
November Weather	16°C (61°F)	67 mm (2.6 inches)	81%	high
December Weather	14°C (58°F)	105 mm (4.1 inches)	84%	moderate