January weather forecastSan Diego, CA
January
Weather in January
January in San Diego rings in the New Year with slightly cooler temperatures and increased precipitation. This month sees a slight dip in average high temperature from 64.2°F (17.9°C) to 63.1°F (17.3°C). With an average rainfall of 1.06" (27mm), it is not the wettest month, but it is close. The relatively higher humidity, standing at 60%, combined with the cooler sea and land temperatures, makes the weather feel colder than it actually is. San Diego's weather can often be unpredictable in January, so visitors and residents should be prepared for cloudy days.Temperature
San Diego's weather, upon January's arrival, documents an average high-temperature of a still comfortable 64.2°F (17.9°C), nearly identical to the prior month. During the month of January, San Diego anticipates a mean low-temperature of 52.7°F (11.5°C).Humidity
In January, the average relative humidity is 60%.Rainfall
In San Diego, during January, the rain falls for 5.3 days and regularly aggregates up to 1.06" (27mm) of precipitation. Throughout the year, there are 61.8 rainfall days, and 8.7" (221mm) of precipitation is accumulated.Ocean temperature
In January, the average ocean temperature in San Diego is 59.4°F (15.2°C).Note: Most individuals do not find swimming at 59.4°F (15.2°C) to be enjoyable. As the water temperature declines below 69.8°F (21°C), maintaining control over one's breathing becomes harder.
Daylight
In January, the average length of the day is 10h and 17min.On the first day of the month, sunrise is at 6:50 am and sunset at 4:53 pm. On the last day of January, sunrise is at 6:44 am and sunset at 5:20 pm PST.
Sunshine
In January, the average sunshine in San Diego is 6.8h.UV index
The months with the lowest UV index in San Diego are January through March, November and December, with an average maximum UV index of 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: The maximum daily UV index of 4 in January converts into the following recommendations:
Put precautions into practice - Ensuring skin and eye safety is a necessity. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in January
San Diego, CA
- Average high temperature in January: 64.2°F
The warmest month (with the highest average high temperature) is August (77.4°F).
The month with the lowest average high temperature is February (63.1°F).
- Average low temperature in January: 52.7°F
The month with the highest average low temperature is August (65.7°F).
The coldest month (with the lowest average low temperature) is February (51.8°F).
Average pressure in January
San Diego, CA
- Average pressure in January: 30.09"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are June and September (29.88"Hg).
Average wind speed in January
San Diego, CA
- Average wind speed in January: 5.3mph
The windiest months (with the highest average wind speed) are April and May (6.3mph).
The calmest month (with the lowest average wind speed) is October (5.2mph).
Average humidity in January
San Diego, CA
- Average humidity in January: 60%
The month with the highest relative humidity is June (73%).
The month with the lowest relative humidity is November (59%).
Average rainfall in January
San Diego, CA
- Average rainfall in January: 1.06"
The wettest month (with the highest rainfall) is December (1.65").
The driest month (with the least rainfall) is June (0.12").
Average rainfall days in January
San Diego, CA
- Average rainfall days in January: 5.3 days
The month with the highest number of rainy days is March (7.6 days).
The month with the least rainy days is June (2.7 days).
Average sea temperature in January
San Diego, CA
- Average sea temperature in January: 59.2°F
The best month for swimming (with the highest average sea temperature) is August (67.9°F).
The coldest month (with the lowest average sea temperature) is February (58.7°F).
Average daylight in January /
Average sunshine in January
San Diego, CA
- Average daylight in January: 10h and 18min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in January: 6h and 48min
The months with the most sunshine are July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).
Average sunshine days in January
San Diego, CA
- Average sunshine days in January: 24.3 days
The month with the most sunshine days is January (24.3 days).
The month with the least sunshine days is July (20.3 days).
Average UV index in January
San Diego, CA
- Average UV index in January: 4
The months with the highest UV index are July, August and September (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 4).
Average cloud cover in January
San Diego, CA
- Average cloud cover in January: 21
The month with the most cloud cover is December (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 9).
Average visibility in January
San Diego, 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).
