Grass Valley (CA)
September
Weather in Grass Valley, California for September 2026
Your guide to Grass Valley weather in September - trends and predictions
In general, the average temperature in Grass Valley at the beginning of September is 32.9 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 25.9 °F by the end of September.
Precipitation in Grass Valley during September is a rare event, with an average of fewer than 2 rainy days.
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Temperatures
Rain 🌧️
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30
Dry days
0
Rainy days
0
Snow days
29°/19°
Temperatures
14 km/h
Avg max wind
44 %
Avg humidity
Grass Valley Weather September
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Temperatures trend during September in Grass Valley
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September weather in Grass Valley day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 39° /24° | 0 mm | 9 | |
| Sept. 2 | Sunny | 35° /24° | 0 mm | 9 | |
| Sept. 3 | Sunny | 35° /23° | 0 mm | 9 | |
| Sept. 4 | Sunny | 34° /23° | 0 mm | 8 | |
| Sept. 5 | Sunny | 31° /20° | 0 mm | 8 | |
| Sept. 6 | Sunny | 29° /19° | 0 mm | 7 | |
| Sept. 7 | Sunny | 27° /18° | 0 mm | 7 | |
| Sept. 8 | Sunny | 27° /17° | 0 mm | 7 | |
| Sept. 9 |  Thundery outbreaks possible | 21° /15° | 0 mm | 5 | |
| Sept. 10 | Thundery outbreaks possible | 20° /14° | 0 mm | 5 | |
| Sept. 11 |  Cloudy | 23° /14° | 0 mm | 5 | |
| Sept. 12 | Sunny | 29° /16° | 0 mm | 7 | |
| Sept. 13 | Sunny | 29° /18° | 0 mm | 7 | |
| Sept. 14 | Sunny | 29° /17° | 0 mm | 7 | |
| Sept. 15 | Sunny | 33° /19° | 0 mm | 8 | |
| Sept. 16 | Sunny | 35° /21° | 0 mm | 9 | |
| Sept. 17 | Sunny | 35° /21° | 0 mm | 9 | |
| Sept. 18 |  Overcast | 27° /22° | 0 mm | 6 | |
| Sept. 19 | Overcast | 22° /16° | 0 mm | 5 | |
| Sept. 20 | Sunny | 29° /18° | 0 mm | 7 | |
| Sept. 21 |  Partly cloudy | 29° /18° | 0 mm | 7 | |
| Sept. 22 | Sunny | 31° /19° | 0 mm | 8 | |
| Sept. 23 | Sunny | 36° /22° | 0 mm | 9 | |
| Sept. 24 | Cloudy | 32° /23° | 0 mm | 7 | |
| Sept. 25 | Overcast | 25° /19° | 0 mm | 6 | |
| Sept. 26 | Sunny | 32° /17° | 0 mm | 8 | |
| Sept. 27 | Sunny | 31° /21° | 0 mm | 8 | |
| Sept. 28 | Partly cloudy | 22° /14° | 0 mm | 6 | |
| Sept. 29 | Overcast | 20° /14° | 0 mm | 5 | |
| Sept. 30 | Overcast | 19° /15° | 0 mm | 4 | |
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Important Notice
Our weather forecast for Grass Valley 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 Grass Valley forecast closer to your planned date for the most up-to-date weather information.
Change Month
Grass Valley in September - FAQ
What are the expected maximum and minimum temperatures in Grass Valley during September?
During September, expect a variety of temperatures with highs around 29° and lows near 19°, suitable for diverse activities and preferences.
How much rainfall should be expected in Grass Valley during September?
Rainfall in Grass Valley during September is rare to nonexistent, with the total expected rainfall being less than 10 mm and approximately 0 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 Grass Valley during September?
The average wind speed in Grass Valley during September is 14 km/h, suggesting breezy to windy conditions, depending on your activities.
UV exposure in Grass Valley during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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