September Weather in Pleasanton, United States

Last updated: June 24, 2025

In Pleasanton, United States, the average temperature in September hovers around 28°C (82°F), with lows dipping to 13°C (55°F) and highs soaring to 40°C (103°F). Expect about 108 mm (4.3 in) of precipitation spread over 9 days throughout the month, while humidity levels hold steady at an average of 65%.

September Temperature in Pleasanton

In September in Pleasanton, the average temperature is 28°C (82°F). Maximum temperatures can reach 40°C (103°F), while minimums can drop as low as 13°C (55°F). It's advisable to pack lightweight clothing for the day and a light jacket for cooler evenings when traveling.

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

The chart illustrates September temperature patterns in Pleasanton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Pleasanton, September typically has an average temperature of 28°C (82°F), with highs reaching up to 40°C (103°F) and lows dropping to around 13°C (55°F).

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

September Precipitation in Pleasanton

In Pleasanton in September, the precipitation amount is 108 mm (4.3 in) spread over 9 days.

September Precipitation Trends in Pleasanton

The chart displays monthly precipitation patterns in Pleasanton, 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 Pleasanton, September typically receives around 108 mm (4.3 inches) of precipitation spread over approximately 9 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 Pleasanton

In Pleasanton in September, humidity is 65%. With an average temperature of 28°C (82°F), this humidity feels like a warm, sticky embrace that can make outdoor activities feel a bit more exhausting, so staying hydrated and taking breaks in the shade is essential for a comfortable travel experience.

September Average Humidity in Pleasanton

This chart illustrates the average monthly humidity levels in Pleasanton, 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 Pleasanton is approximately 65%, 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 Pleasanton

In Pleasanton 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 Pleasanton.

Maximum UV Index Levels in Pleasanton for September

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

Data source: Pleasanton 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 Pleasanton Compares to Other Months

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

This table compares monthly weather conditions in Pleasanton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	13°C (55°F)	32 mm (1.3 inches)	79%	moderate
February Weather	14°C (58°F)	46 mm (1.8 inches)	79%	very high
March Weather	20°C (67°F)	53 mm (2.1 inches)	74%	very high
April Weather	22°C (73°F)	52 mm (2.0 inches)	76%	extreme
May Weather	26°C (80°F)	103 mm (4.1 inches)	81%	extreme
June Weather	29°C (85°F)	64 mm (2.5 inches)	76%	extreme
July Weather	30°C (87°F)	72 mm (2.8 inches)	66%	extreme
August Weather	31°C (88°F)	52 mm (2.1 inches)	58%	extreme
September Weather	28°C (82°F)	108 mm (4.3 inches)	65%	extreme
October Weather	23°C (74°F)	76 mm (3.0 inches)	74%	very high
November Weather	17°C (64°F)	43 mm (1.7 inches)	81%	high
December Weather	14°C (58°F)	43 mm (1.7 inches)	86%	moderate