San Joaquin County
September
Weather in San Joaquin County for September 2025
Your guide to San Joaquin County weather in September - trends and predictions
In general, the average temperature in San Joaquin County at the beginning of September is 34.6 °F. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 32 °F by the end of September.
Precipitation in San Joaquin 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
31°/12°
Temperatures
16 km/h
Avg max wind
56 %
Avg humidity
San Joaquin County in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  30° | 2 31° | 3 33° | 4  36° | 5 38° | 6  38° | 7  36° |
| 8 36° | 9 36° | 10 34° | 11  34° | 12 32° | 13 34° | 14 35° |
| 15 29° | 16 27° | 17 26° | 18 26° | 19 31° | 20 31° | 21 32° |
| 22 33° | 23 33° | 24 34° | 25 30° | 26 31° | 27 34° | 28 33° |
| 29 34° | 30  28° |
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Temperatures trend during September in San Joaquin County
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 | Overcast | 30° /15° | 0 mm | 7 | |
| Sept. 2 | Overcast | 31° /13° | 0 mm | 7 | |
| Sept. 3 | Overcast | 33° /15° | 0 mm | 8 | |
| Sept. 4 | Mist | 36° /16° | 0 mm | 9 | |
| Sept. 5 | Mist | 38° /16° | 0 mm | 9 | |
| Sept. 6 | Sunny | 38° /17° | 0 mm | 10 | |
| Sept. 7 | Partly cloudy | 36° /16° | 0 mm | 9 | |
| Sept. 8 | Sunny | 36° /15° | 0 mm | 9 | |
| Sept. 9 | Partly cloudy | 36° /14° | 0 mm | 9 | |
| Sept. 10 | Mist | 34° /13° | 0 mm | 8 | |
| Sept. 11 | Cloudy | 34° /12° | 0 mm | 8 | |
| Sept. 12 | Overcast | 32° /13° | 0 mm | 8 | |
| Sept. 13 | Mist | 34° /13° | 0 mm | 8 | |
| Sept. 14 | Partly cloudy | 35° /15° | 0 mm | 9 | |
| Sept. 15 | Partly cloudy | 29° /13° | 0 mm | 7 | |
| Sept. 16 | Cloudy | 27° /13° | 0.1 mm | 6 | |
| Sept. 17 | Overcast | 26° /11° | 0 mm | 6 | |
| Sept. 18 | Mist | 26° /12° | 0 mm | 6 | |
| Sept. 19 | Mist | 31° /12° | 0 mm | 7 | |
| Sept. 20 | Mist | 31° /12° | 0 mm | 7 | |
| Sept. 21 | Cloudy | 32° /10° | 0 mm | 7 | |
| Sept. 22 | Cloudy | 33° /11° | 0 mm | 8 | |
| Sept. 23 | Overcast | 33° /12° | 0 mm | 8 | |
| Sept. 24 | Mist | 34° /13° | 0 mm | 7 | |
| Sept. 25 | Mist | 30° /13° | 0 mm | 7 | |
| Sept. 26 | Overcast | 31° /10° | 0 mm | 7 | |
| Sept. 27 | Mist | 34° /11° | 0 mm | 8 | |
| Sept. 28 | Mist | 33° /12° | 0 mm | 8 | |
| Sept. 29 | Partly cloudy | 34° /10° | 0 mm | 8 | |
| Sept. 30 | Light rain shower | 28° /12° | 1.9 mm | 7 | |
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Important Notice
Our weather forecast for San Joaquin 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 San Joaquin County forecast closer to your planned date for the most up-to-date weather information.
San Joaquin County in September - FAQ
What are the expected maximum and minimum temperatures in San Joaquin County during September?
Expect warm days with temperatures around 31°, cooling to mild conditions of 12° after sunset. Perfect for those who enjoy warm weather.
How much rainfall should be expected in San Joaquin County during September?
Rainfall in San Joaquin 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 San Joaquin County during September?
The average wind speed in San Joaquin County during September is 16 km/h, suggesting breezy to windy conditions, depending on your activities.
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Where is San Joaquin County?Get accurate weather forecasts for San Joaquin County, located at latitude 37.958 and longitude -121.291. Stay updated with localized weather information tailored for San Joaquin County.
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