Alameda County
September
Weather in Alameda County for September 2025
Your guide to Alameda County weather in September - trends and predictions
In general, the average temperature in Alameda County at the beginning of September is 21.3 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 17.9 °F by the end of September.
Precipitation in Alameda County during September is a rare event, with an average of fewer than 2 rainy days.
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29
Dry days
1
Rainy days
0
Snow days
20°/13°
Temperatures
19 km/h
Avg max wind
82 %
Avg humidity
Alameda County in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  19° | 2  20° | 3 23° | 4 22° | 5 23° | 6 21° | 7 21° |
| 8 21° | 9 20° | 10 19° | 11 21° | 12 20° | 13 21° | 14 21° |
| 15 18° | 16 19° | 17  16° | 18 18° | 19 15° | 20 17° | 21 17° |
| 22 17° | 23 18° | 24 17° | 25 17° | 26 18° | 27 18° | 28 17° |
| 29  17° | 30 21° |
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Temperatures trend during September in Alameda County
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September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 | Patchy rain possible | 19° /13° | 0.1 mm | 4 | |
| Sept. 2 | Mist | 20° /14° | 0 mm | 5 | |
| Sept. 3 | Mist | 23° /13° | 0 mm | 6 | |
| Sept. 4 | Mist | 22° /14° | 0 mm | 6 | |
| Sept. 5 | Mist | 23° /13° | 0 mm | 6 | |
| Sept. 6 | Mist | 21° /13° | 0 mm | 6 | |
| Sept. 7 | Mist | 21° /12° | 0 mm | 6 | |
| Sept. 8 | Fog | 21° /12° | 0 mm | 6 | |
| Sept. 9 | Fog | 20° /12° | 0 mm | 5 | |
| Sept. 10 | Fog | 19° /12° | 0 mm | 5 | |
| Sept. 11 | Fog | 21° /12° | 0 mm | 6 | |
| Sept. 12 | Mist | 20° /13° | 0 mm | 5 | |
| Sept. 13 | Fog | 21° /13° | 0 mm | 6 | |
| Sept. 14 | Fog | 21° /13° | 0 mm | 6 | |
| Sept. 15 | Mist | 18° /13° | 0 mm | 5 | |
| Sept. 16 | Mist | 19° /13° | 0.3 mm | 5 | |
| Sept. 17 | Overcast | 16° /13° | 0 mm | 4 | |
| Sept. 18 | Mist | 18° /12° | 0 mm | 5 | |
| Sept. 19 | Fog | 15° /12° | 0 mm | 4 | |
| Sept. 20 | Mist | 17° /12° | 0 mm | 4 | |
| Sept. 21 | Mist | 17° /12° | 0 mm | 4 | |
| Sept. 22 | Fog | 17° /11° | 0 mm | 4 | |
| Sept. 23 | Overcast | 18° /12° | 0 mm | 4 | |
| Sept. 24 | Mist | 17° /11° | 0 mm | 5 | |
| Sept. 25 | Mist | 17° /12° | 0 mm | 4 | |
| Sept. 26 | Patchy rain possible | 18° /12° | 0.1 mm | 5 | |
| Sept. 27 | Mist | 18° /12° | 0 mm | 5 | |
| Sept. 28 | Mist | 17° /11° | 0 mm | 4 | |
| Sept. 29 | Partly cloudy | 17° /12° | 0 mm | 5 | |
| Sept. 30 | Light rain shower | 21° /13° | 1 mm | 5 | |
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Important Notice
Our weather forecast for Alameda County in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Alameda County forecast closer to your planned date for the most up-to-date weather information.
Alameda County in September - FAQ
What are the expected maximum and minimum temperatures in Alameda County during September?
Enjoy moderate daytime temperatures of up to 20° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Alameda County during September?
Rainfall in Alameda County during September is rare to nonexistent, with the total expected rainfall being less than 10 mm and approximately 1 days seeing any precipitation. Planning without the concern for rain is generally straightforward during this very dry period.
What are the typical wind conditions in Alameda County during September?
The average wind speed in Alameda County during September is 19 km/h, suggesting breezy to windy conditions, depending on your activities.
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Where is Alameda County?Get accurate weather forecasts for Alameda County, located at latitude 37.804 and longitude -122.271. Stay updated with localized weather information tailored for Alameda County.
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