September Weather in Mission, United States

Last updated: June 24, 2025

In September, the average temperature in Mission, United States hovers around 18°C (65°F). Temperatures can range from a chilly 3°C (38°F) to a sweltering 37°C (99°F). Expect a modest precipitation amount of 19 mm (0.7 in) over approximately 3 days, accompanied by an average humidity level of 58%.

September Temperature in Mission

In September in Mission, the average temperature is 18°C (65°F). The maximum can reach 37°C (99°F), and the minimum can be as low as 3°C (38°F). It's advisable to pack for both warm and cool weather to ensure a comfortable trip.

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

The chart illustrates September temperature patterns in Mission, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mission, September typically has an average temperature of 18°C (65°F), with highs reaching up to 37°C (99°F) and lows dropping to around 3°C (38°F).

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

September Precipitation in Mission

In Mission in September, the precipitation amount is 19 mm (0.7 in) over a period of 3 days.

September Precipitation Trends in Mission

The chart displays monthly precipitation patterns in Mission, 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 Mission, September typically receives around 19 mm (0.7 inches) of precipitation spread over approximately 3 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 Mission

In Mission in September humidity is 58%. With an average temperature of 18°C (65°F), this humidity feels like a warm embrace, creating a comfortable yet slightly muggy atmosphere perfect for leisurely exploration.

September Average Humidity in Mission

This chart illustrates the average monthly humidity levels in Mission, 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 Mission is approximately 58%, 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 Mission

In Mission in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Mission.

Maximum UV Index Levels in Mission for September

The chart shows the monthly maximum UV Index (UVI) for Mission 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 Mission typically reaches 7, which falls under the high exposure category.

Data source: Mission 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 Mission Compares to Other Months

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

This table compares monthly weather conditions in Mission, 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 (36°F)	59 mm (2.3 inches)	86%	low
February Weather	2°C (36°F)	88 mm (3.5 inches)	86%	moderate
March Weather	6°C (44°F)	61 mm (2.4 inches)	85%	high
April Weather	10°C (51°F)	49 mm (1.9 inches)	83%	high
May Weather	15°C (60°F)	34 mm (1.3 inches)	77%	very high
June Weather	20°C (68°F)	16 mm (0.6 inches)	81%	very high
July Weather	25°C (77°F)	0 mm (0.0 inches)	76%	very high
August Weather	24°C (75°F)	8 mm (0.3 inches)	60%	very high
September Weather	18°C (65°F)	19 mm (0.7 inches)	58%	high
October Weather	11°C (52°F)	45 mm (1.8 inches)	75%	moderate
November Weather	6°C (42°F)	63 mm (2.5 inches)	85%	moderate
December Weather	2°C (36°F)	63 mm (2.5 inches)	87%	low