September weather forecast
Oakland, CA

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Weather in September

September marks the commencement of fall in Oakland, California, bringing a mild decrease in temperature. The duration of daylight lessens slightly, yet people continue to enjoy ample sunshine hours. Relative humidity and pressure remain relatively stable, contributing to a comfortable external environment. Despite these changes, September records the highest sea temperature of 57.3°F (14.1°C), inviting maritime enthusiasts to partake in various water sports. As October greets Oakland, a notable drop in numerous weather attributes becomes evident.

Temperature

In Oakland, California, temperatures reach their average annual highs in September, measuring 73.9°F (23.3°C) and a minimum average of 56.5°F (13.6°C).

Humidity

In Oakland, the average relative humidity in September is 68%.

Rainfall

In September, in Oakland, the rain falls for 1.8 days. Throughout September, 0.04" (1mm) of precipitation is accumulated. Throughout the year, in Oakland, there are 44 rainfall days, and 3.03" (77mm) of precipitation is accumulated.

Ocean temperature

With an average ocean temperature of 57.4°F (14.1°C), September is the month with the warmest seawater.
Note: To swim in 57.4°F (14.1°C) at less than 50°F (10°C), ensure you're well-protected. Without it, be prepared for a sudden jolt of cold and breathing issues. Remember, even 55.4°F (13°C) is not welcoming.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of September in Oakland, sunrise is at 6:39 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:53 pm PDT.

Sunshine

In Oakland, the average sunshine in September is 11h.

UV index

April through September, with an average maximum UV index of 5, are months with the highest UV index in Oakland. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The daily high UV index of 5 during September translates into the following recommendations:
Undertake precautions - It is suggested to shield oneself from sunburn. When the Sun is at its strongest around midday, find shade and limit exposure. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
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Frequently asked questions

What part of the year is the hottest in Oakland?

In Oakland, September is the warmest month, with temperatures averaging a high of 73.9°F (23.3°C) and a low of 56.5°F (13.6°C).

What are September temperatures in Oakland?

An average high-temperature, in September, in Oakland, is 73.9°F (23.3°C) and the average low-temperature is 56.5°F (13.6°C).

What is the average humidity in September in Oakland?

In September, the average relative humidity in Oakland, California, is 68%.

How much does it rain in Oakland in September?

In September, the rain falls for 1.8 days. Throughout September, 0.04" (1mm) of precipitation is accumulated.

When is the ocean warmest in Oakland?

With an average ocean temperature of 57.4°F (14.1°C), September is the month with the warmest seawater in Oakland.

What is the water temperature in September in Oakland?

In September, the average ocean temperature is 57.4°F (14.1°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

How many hours of daylight does Oakland have in September?

In Oakland, the average day length in September is 12h and 25min.

What time are sunrise and sunset in September in Oakland?

On the first day of September, sunrise is at 6:39 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:53 pm PDT.

How many hours of sunshine does Oakland have in September?

In Oakland, the average sunshine duration in September is 11h.

What is the month with the highest UV index in Oakland?

The months with the highest UV index in Oakland, California, are April through September, with an average maximum UV index of 5.

How high is the UV index in September in Oakland?

In September, the average daily maximum UV index in Oakland, California, is 5. A UV Index estimate of 3 to 5 represents a medium hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Oakland, CA

Average temperature in September - Oakland, CA
  • Average high temperature in September: 73.9°F

The warmest month (with the highest average high temperature) is September (73.9°F).
The month with the lowest average high temperature is December (55.8°F).

  • Average low temperature in September: 56.5°F

The month with the highest average low temperature is September (56.5°F).
The coldest month (with the lowest average low temperature) is January (45.7°F).

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Average pressure in September
Oakland, CA

Average pressure in September - Oakland, CA
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

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Average wind speed in September
Oakland, CA

Average wind speed in September - Oakland, CA
  • Average wind speed in September: 5.7mph

The windiest month (with the highest average wind speed) is May (7.6mph).
The calmest months (with the lowest average wind speed) are October and November (5.5mph).

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Average humidity in September
Oakland, CA

Average humidity in September - Oakland, CA
  • Average humidity in September: 68%

The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is October (67%).

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Average rainfall in September
Oakland, CA

Average rainfall in September - Oakland, CA
  • Average rainfall in September: 0.04"

The wettest month (with the highest rainfall) is February (0.67").
The driest month (with the least rainfall) is July (0").

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Average rainfall days in September
Oakland, CA

Average rainfall days in September - Oakland, CA
  • Average rainfall days in September: 1.8 days

The month with the highest number of rainy days is March (8.5 days).
The months with the least rainy days are June and August (0.8 days).

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Average sea temperature in September
Oakland, CA

Average sea temperature in September - Oakland, CA
  • Average sea temperature in September: 57.3°F

The best month for swimming (with the highest average sea temperature) is September (57.3°F).
The coldest months (with the lowest average sea temperature) are April and June (53°F).

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Average daylight in September /
Average sunshine in September
Oakland, CA

Average daylight in September / Average sunshine in September - Oakland, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in September: 11h and 0min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).

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Average sunshine days in September
Oakland, CA

Average sunshine days in September - Oakland, CA
  • Average sunshine days in September: 27.9 days

The month with the most sunshine days is July (29.7 days).
The month with the least sunshine days is March (20.8 days).

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Average UV index in September
Oakland, CA

Average UV index in September - Oakland, CA
  • Average UV index in September: 5

The months with the highest UV index are April, May, June, July, August and September (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in September
Oakland, CA

Average cloud cover in September - Oakland, CA
  • Average cloud cover in September: 13

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 12).

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Average visibility in September
Oakland, CA

Average visibility in September - Oakland, CA
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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Oakland, California, USA

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