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Weather in San Mateo County, California for January 2026

Your guide to San Mateo County weather in January - trends and predictions

    Official Weather Alert ⚠️

  • Coastal Flood Advisory - See hour by hour.

    • Temperatures

  • Until now, January 2026 in San Mateo County has been nearly identical to the historical average, with a temperature of 13.6 °F (showing only a slight deviation of 0.4 °F).

  • The forecast for the next days in San Mateo County predicts a temperature of 15.9 °F, which is cooler than the historical average.

  • In general, the average temperature in San Mateo County at the beginning of January is 13.1 °F. As the month progressed, temperatures tended to moderately rise, reaching an average of 14 °F by the end of January.

    • Rain 🌧️

  • With an average of 2 rainy days, San Mateo County experiences minimal rainfall in January.

    • More

  • New! Chat with our AI weatherman - it’s amazing and free.

Average dry days
29
Dry days
Average rainy days
2
Rainy days
Average snowy days
0
Snow days
Average temperatures
12°/7°
Temperatures
Average wind speed
12 km/h
Avg max wind
Average humidity
78 %
Avg humidity

San Mateo County Weather January

Move between months or click on a day
December
February
Sun.Mon.Tue.Wed.Thu.Fri.Sat.
1
Cloudy
13°
2
Partly cloudy
14°
3
Heavy rain at times
14°
4
Overcast
13°
5
Overcast
13°
6
Overcast
12°
7
Sunny
13°
8
Cloudy
12°
9
Overcast
15°
10
Cloudy
13°
11
Overcast
14°
12
Sunny
12°
13
Sunny
14°
14
Sunny
14°
15
Cloudy
16°
16
Partly cloudy
16°
17
Overcast
13°
18
Overcast
10°
19
Overcast
13°
20
Overcast
13°
21
Partly cloudy
13°
22
Sunny
13°
23
Sunny
12°
24
Overcast
14°
25
Patchy rain possible
12°
26
Partly cloudy
12°
27
Sunny
13°
28
Overcast
13°
29
Overcast
11°
30
Weather Alert Sunny
20°
31
Partly cloudy
17°

Temperatures trend during January in San Mateo County

See the weather trend as well as the moving average line

January weather in San Mateo County day by day

Click on a date for more information
December February
Date Weather Temperatures Rain UV More
Jan. 1 Cloudy
Cloudy
 13° /8° 4.3 mm 2
Jan. 2 Partly cloudy
Partly cloudy
 14° /10° 0 mm 3
Jan. 3 Heavy rain at times
Heavy rain at times
 14° /11° 19.8 mm 2
Jan. 4 Overcast
Overcast
 13° /8° 39.1 mm 2
Jan. 5 Overcast
Overcast
 13° /8° 0 mm 2
Jan. 6 Overcast
Overcast
 12° /7° 0 mm 2
Jan. 7 Sunny
Sunny
 13° /9° 1.7 mm 2
Jan. 8 Cloudy
Cloudy
 12° /8° 0 mm 2
Jan. 9 Overcast
Overcast
 15° /5° 0 mm 3
Jan. 10 Cloudy
Cloudy
 13° /3° 0 mm 2
Jan. 11 Overcast
Overcast
 14° /4° 0 mm 2
Jan. 12 Sunny
Sunny
 12° /6° 0 mm 2
Jan. 13 Sunny
Sunny
 14° /4° 0 mm 3
Jan. 14 Sunny
Sunny
 14° /5° 0 mm 3
Jan. 15 Cloudy
Cloudy
 16° /4° 0 mm 2
Jan. 16 Partly cloudy
Partly cloudy
 16° /5° 0 mm 3
Jan. 17 Overcast
Overcast
 13° /5° 0 mm 2
Jan. 18 Overcast
Overcast
 10° /6° 0 mm 3
Jan. 19 Overcast
Overcast
 13° /7° 0 mm 2
Jan. 20 Overcast
Overcast
 13° /4° 0 mm 2
Jan. 21 Partly cloudy
Partly cloudy
 13° /6° 0 mm 2
Jan. 22 Sunny
Sunny
 13° /8° 0 mm 2
Jan. 23 Sunny
Sunny
 12° /7° 0 mm 3
Jan. 24 Overcast
Overcast
 14° /6° 0 mm 2
Jan. 25 Patchy rain possible
Patchy rain possible
 12° /5° 0.1 mm 2
Jan. 26 Partly cloudy
Partly cloudy
 12° /5° 0 mm 3
Jan. 27 Sunny
Sunny
 13° /6° 0 mm 2
Jan. 28 Overcast
Overcast
 13° /8° 0 mm 2
Jan. 29 Overcast
Overcast
 11° /5° 0 mm 2
Jan. 30 Sunny
Sunny
 20° /8° 0 mm 0.6
Jan. 31 Partly cloudy
Partly cloudy
 17° /6° 0 mm 0.6
Next
Important Notice
Our weather forecast for San Mateo County in January 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 County forecast closer to your planned date for the most up-to-date weather information.
Change Month
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San Mateo County in January - FAQ

What are the expected maximum and minimum temperatures in San Mateo County during January?

During January, expect a variety of temperatures with highs around 12° and lows near 7°, suitable for diverse activities and preferences.

How much rainfall should be expected in San Mateo County during January?

Expect minimal rainfall in San Mateo County during January, with a total of 20 mm over approximately 2 days. This minimal precipitation is unlikely to significantly impact plans.

What are the typical wind conditions in San Mateo County during January?

The average wind speed in San Mateo County during January is 12 km/h, suggesting breezy to windy conditions, depending on your activities.

January rainfall patterns in San Mateo County

Explore the daily rainfall trends and prepare for San Mateo Countys January weather 💧
Typically, San Mateo County has 2 rainy days in January with a total of 20 mm of rainfall.
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Location coordinates Where is San Mateo County?

Get accurate weather forecasts for San Mateo County, located at latitude 37.563 and longitude -122.326. Stay updated with localized weather information tailored for San Mateo County.

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