Contents
- Weather in January
- Frequently asked questions
- Average temperature in January
- Average pressure in January
- Average wind speed in January
- Average humidity in January
- Average rainfall in January
- Average rainfall days in January
- Average daylight in January
- Average sunshine in January
- Average sunshine days in January
- Average UV index in January
- Average cloud cover in January
- Average visibility in January
Weather in January
Temperature
The advent of January reveals an average high-temperature of a still moderate 56.8°F (13.8°C), showing minimal difference from the prior month. San Mateo reports a consistent average low-temperature of 46.9°F (8.3°C) throughout January nights.Humidity
In San Mateo, the average relative humidity in January is 73%.Rainfall
In San Mateo, during January, the rain falls for 4.4 days and regularly aggregates up to 0.31" (8mm) of precipitation. In San Mateo, during the entire year, the rain falls for 32.6 days and collects up to 2.13" (54mm) of precipitation.Daylight
In San Mateo, the average length of the day in January is 9h and 55min.On the first day of the month, sunrise is at 7:24 am and sunset at 5:01 pm. On the last day of January, sunrise is at 7:13 am and sunset at 5:31 pm PST.
Sunshine
In January, the average sunshine is 6.2h.UV index
In January, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the ordinary person.Note: An average UV index of 4 in January transforms into this advice:
Prioritize safety - Suggestions to prevent sun damage are offered. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for San Mateo in January?
What is the average humidity in January in San Mateo?
How many days does it rain in January?
What is the average length of the day in January?
What time are sunrise and sunset in January?
How long on average sun shines in January?
What is the UV index reading in January?
Average temperature in January
San Mateo, CA
- Average high temperature in January: 56.8°F
The warmest months (with the highest average high temperature) are August and September (71.2°F).
The month with the lowest average high temperature is December (55.8°F).
- Average low temperature in January: 46.9°F
The month with the highest average low temperature is September (56.7°F).
The coldest month (with the lowest average low temperature) is January (46.9°F).
Average pressure in January
San Mateo, CA
- Average pressure in January: 30.13"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).
Average wind speed in January
San Mateo, CA
- Average wind speed in January: 6.2mph
The windiest month (with the highest average wind speed) is April (8mph).
The calmest months (with the lowest average wind speed) are August, September and October (5.9mph).
Average humidity in January
San Mateo, CA
- Average humidity in January: 73%
The months with the highest relative humidity are March and August (76%).
The months with the lowest relative humidity are October and November (70%).
Average rainfall in January
San Mateo, CA
- Average rainfall in January: 0.31"
The wettest month (with the highest rainfall) is February (0.55").
The driest months (with the least rainfall) are June, July and August (0").
Average rainfall days in January
San Mateo, CA
- Average rainfall days in January: 4.4 days
The month with the highest number of rainy days is March (6.8 days).
The month with the least rainy days is July (0.3 days).
Average daylight in January /
Average sunshine in January
San Mateo, CA
- Average daylight in January: 9h and 5min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in January: 6h and 1min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days in January
San Mateo, CA
- Average sunshine days in January: 25 days
The month with the most sunshine days is July (30.4 days).
The month with the least sunshine days is February (23.3 days).
Average UV index in January
San Mateo, CA
- Average UV index in January: 4
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February and December (UV index 3).
Average cloud cover in January
San Mateo, CA
- Average cloud cover in January: 32
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 11).
Average visibility in January
San Mateo, CA
- Average visibility in January: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
San Mateo, California, USA
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