San Mateo (CA)
December
Weather in San Mateo, California for December 2025
Your guide to San Mateo weather in December - trends and predictions
In general, the average temperature in San Mateo at the beginning of December is 13 °F. As the month progressed, temperatures tended to moderately fall, reaching an average of 11.7 °F by the end of December.
The climate of San Mateo in December is notably wet, with an average of 13 rainy days, and a total of 172.9 mm of precipitation.
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Temperatures
Rain 🌧️
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18
Dry days
13
Rainy days
0
Snow days
13°/9°
Temperatures
14 km/h
Avg max wind
86 %
Avg humidity
San Mateo Weather December
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Temperatures trend during December in San Mateo
See the weather trend as well as the moving average line
December weather in San Mateo day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Dec. 1 |  Heavy rain at times | 16° /10° | 1.1 mm | 4 | |
| Dec. 2 |  Cloudy | 13° /8° | 0 mm | 3 | |
| Dec. 3 |  Overcast | 12° /8° | 0 mm | 3 | |
| Dec. 4 | Cloudy | 13° /8° | 0 mm | 3 | |
| Dec. 5 | Overcast | 12° /9° | 0 mm | 3 | |
| Dec. 6 | Overcast | 13° /9° | 0 mm | 3 | |
| Dec. 7 | Overcast | 12° /8° | 0 mm | 3 | |
| Dec. 8 | Overcast | 13° /9° | 0 mm | 3 | |
| Dec. 9 |  Partly cloudy | 14° /7° | 0 mm | 4 | |
| Dec. 10 |  Sunny | 14° /6° | 0 mm | 4 | |
| Dec. 11 | Partly cloudy | 14° /6° | 0 mm | 4 | |
| Dec. 12 | Heavy rain at times | 11° /10° | 24.5 mm | 3 | |
| Dec. 13 |  Moderate rain at times | 13° /9° | 2.2 mm | 3 | |
| Dec. 14 | Moderate or heavy rain shower | 12° /10° | 51 mm | 3 | |
| Dec. 15 | Overcast | 9° /6° | 0 mm | 2 | |
| Dec. 16 | Moderate or heavy rain shower | 11° /8° | 8.4 mm | 3 | |
| Dec. 17 | Overcast | 11° /9° | 0 mm | 3 | |
| Dec. 18 | Overcast | 11° /8° | 0 mm | 3 | |
| Dec. 19 | Overcast | 14° /6° | 0 mm | 3 | |
| Dec. 20 | Overcast | 13° /7° | 0 mm | 3 | |
| Dec. 21 | Moderate or heavy rain shower | 12° /10° | 4.9 mm | 3 | |
| Dec. 22 |  Patchy rain possible | 15° /12° | 0.6 mm | 4 | |
| Dec. 23 | Patchy rain possible | 16° /13° | 0.4 mm | 4 | |
| Dec. 24 | Moderate or heavy rain shower | 14° /10° | 31 mm | 3 | |
| Dec. 25 | Overcast | 10° /7° | 0 mm | 3 | |
| Dec. 26 | Moderate or heavy rain shower | 13° /9° | 11.8 mm | 3 | |
| Dec. 27 | Moderate or heavy rain shower | 14° /12° | 29.2 mm | 3 | |
| Dec. 28 | Moderate rain at times | 14° /11° | 1.3 mm | 3 | |
| Dec. 29 | Moderate or heavy rain shower | 13° /9° | 6.5 mm | 3 | |
| Dec. 30 | Overcast | 11° /7° | 0 mm | 3 | |
| Dec. 31 |  Fog | 7° /3° | 0 mm | 2 | |
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Important Notice
Our weather forecast for San Mateo 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 Mateo forecast closer to your planned date for the most up-to-date weather information.
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San Mateo in December - FAQ
What are the expected maximum and minimum temperatures in San Mateo during December?
During December, expect a variety of temperatures with highs around 13° and lows near 9°, suitable for diverse activities and preferences.
How much rainfall should be expected in San Mateo during December?
Significant rainfall exceeding 172.9 mm is expected in San Mateo during December, occurring over more than 13 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in San Mateo during December?
The average wind speed in San Mateo during December is 14 km/h, suggesting breezy to windy conditions, depending on your activities.
December rainfall patterns in San Mateo
Explore the daily rainfall trends and prepare for San Mateos December weather 💧
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