September Weather in Oakland, United States

Last updated: June 24, 2025

In September, the average temperature in Oakland, United States hovers around 27°C (81°F). On cooler days, temperatures can dip to a minimum of 18°C (65°F), while heat waves can push the mercury as high as 34°C (94°F). Be prepared for the weather; with an average precipitation of 183 mm (7.2 in) spread over 19 days, and humidity levels reaching 83%, it’s a season best enjoyed with light clothing and an umbrella in hand!

September Temperature in Oakland

In September in Oakland, the average temperature is 27°C (81°F), with maximums reaching up to 34°C (94°F) and minimums dropping as low as 18°C (65°F). This pleasant climate makes it an ideal time for travelers to explore and enjoy outdoor activities.

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

The chart illustrates September temperature patterns in Oakland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Oakland, September typically has an average temperature of 27°C (81°F), with highs reaching up to 34°C (94°F) and lows dropping to around 18°C (65°F).

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

September Precipitation in Oakland

In Oakland in September, the total precipitation amount is 183 mm (7.2 in) over a span of 19 days.

September Precipitation Trends in Oakland

The chart displays monthly precipitation patterns in Oakland, 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 Oakland, September typically receives around 183 mm (7.2 inches) of precipitation spread over approximately 19 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 Oakland

In Oakland in September humidity is 83%. With an average temperature of 27°C (81°F), this humidity feels like a warm blanket enveloping you, making sightseeing and outdoor activities feel more exhausting and requiring frequent breaks to relax in the shade or cool off.

September Average Humidity in Oakland

This chart illustrates the average monthly humidity levels in Oakland, 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 Oakland is approximately 83%, 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 Oakland

In Oakland 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 Oakland.

Maximum UV Index Levels in Oakland for September

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

Data source: Oakland 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 Oakland Compares to Other Months

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

This table compares monthly weather conditions in Oakland, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	16°C (60°F)	43 mm (1.7 inches)	83%	moderate
February Weather	19°C (66°F)	54 mm (2.1 inches)	80%	very high
March Weather	20°C (68°F)	19 mm (0.8 inches)	75%	very high
April Weather	23°C (73°F)	75 mm (2.9 inches)	70%	extreme
May Weather	25°C (78°F)	105 mm (4.1 inches)	68%	extreme
June Weather	27°C (81°F)	213 mm (8.4 inches)	75%	extreme
July Weather	27°C (82°F)	243 mm (9.6 inches)	79%	extreme
August Weather	28°C (82°F)	233 mm (9.2 inches)	81%	extreme
September Weather	27°C (81°F)	183 mm (7.2 inches)	83%	extreme
October Weather	25°C (77°F)	84 mm (3.3 inches)	81%	very high
November Weather	20°C (68°F)	46 mm (1.8 inches)	82%	high
December Weather	17°C (63°F)	65 mm (2.6 inches)	84%	moderate