San Bernardino County (San Bernardino)
December
Weather in San Bernardino County, California for December 2025
Your guide to San Bernardino County weather in December - trends and predictions
So far, December 2025 in San Bernardino County is slightly warmer than the historical average by 1.7 °F.
Expect cooler weather in the next days in San Bernardino County with the forecast suggesting a temperature of 18.3 °F, lower than the historical average.
In general, the average temperature in San Bernardino County at the beginning of December is 21 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 13.3 °F by the end of December.
San Bernardino County experiences moderate rainfall in December, with an average of 7 rainy days and a total precipitation of 21.6 mm.
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Temperatures
Rain 🌧️
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24
Dry days
7
Rainy days
0
Snow days
18°/8°
Temperatures
8 km/h
Avg max wind
38 %
Avg humidity
San Bernardino County Weather December
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Temperatures trend during December in San Bernardino County
See the weather trend as well as the moving average line
December weather in San Bernardino County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Dec. 1 |  Sunny | 20° /9° | 0 mm | 5 | |
| Dec. 2 | Sunny | 19° /6° | 0 mm | 5 | |
| Dec. 3 | Sunny | 20° /7° | 0 mm | 5 | |
| Dec. 4 | Sunny | 21° /10° | 0 mm | 5 | |
| Dec. 5 | Sunny | 23° /8° | 0 mm | 6 | |
| Dec. 6 | Sunny | 22° /10° | 0 mm | 6 | |
| Dec. 7 | Sunny | 22° /9° | 0 mm | 6 | |
| Dec. 8 | Sunny | 21° /9° | 0 mm | 6 | |
| Dec. 9 | Sunny | 22° /9° | 0 mm | 6 | |
| Dec. 10 | Sunny | 24° /9° | 0 mm | 6 | |
| Dec. 11 |  Overcast | 22° /10° | 0 mm | 5 | |
| Dec. 12 | Sunny | 18° /9° | 0 mm | 5 | |
| Dec. 13 | Sunny | 18° /7° | 0 mm | 5 | |
| Dec. 14 |  Partly cloudy | 19° /9° | 0 mm | 5 | |
| Dec. 15 | Sunny | 21° /8° | 0 mm | 6 | |
| Dec. 16 | Sunny | 23° /10° | 0 mm | 6 | |
| Dec. 17 | Sunny | 28° /10° | 0 mm | 0.7 | |
| Dec. 18 | Sunny | 30° /11° | 0 mm | 0.7 | |
| Dec. 19 | Sunny | 23° /16° | 0 mm | 0.6 | |
| Dec. 20 | Sunny | 22° /14° | 0 mm | 0.6 | |
| Dec. 21 | Sunny | 20° /12° | 0 mm | 0.6 | |
| Dec. 22 | Sunny | 22° /13° | 0 mm | 0 | |
| Dec. 23 |  Patchy rain possible | 18° /9° | 0.4 mm | 3 | |
| Dec. 24 |  Moderate rain | 15° /12° | 8.1 mm | 3 | |
| Dec. 25 | Moderate rain | 13° /10° | 13.1 mm | 3 | |
| Dec. 26 | Moderate rain | 12° /8° | 8.6 mm | 2 | |
| Dec. 27 | Patchy rain possible | 10° /4° | 3.3 mm | 2 | |
| Dec. 28 | Partly cloudy | 12° /3° | 0 mm | 3 | |
| Dec. 29 | Sunny | 14° /3° | 0 mm | 3 | |
| Dec. 30 | Sunny | 17° /2° | 0 mm | 3 | |
| Dec. 31 | Light rain shower | 15° /8° | 2.1 mm | 4 | |
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Important Notice
Our weather forecast for San Bernardino County in December 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 Bernardino County forecast closer to your planned date for the most up-to-date weather information.
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San Bernardino County in December - FAQ
What are the expected maximum and minimum temperatures in San Bernardino County during December?
Enjoy moderate daytime temperatures of up to 18° and cooler nights around 8°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in San Bernardino County during December?
In December, San Bernardino County can expect light to moderate rainfall, totaling 21.6 mm across approximately 7 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in San Bernardino County during December?
The average wind speed in San Bernardino County during December is 8 km/h, suggesting breezy to windy conditions, depending on your activities.
December rainfall patterns in San Bernardino County
Explore the daily rainfall trends and prepare for San Bernardino Countys December weather 💧
Typically, San Bernardino County has 7 rainy days in December with a total of 21.6 mm of rainfall.
UV exposure in San Bernardino County during December
Stay informed about UV levels for safe outdoor activities throughout the month of December ☀️
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