© Giuliano Maciocci/stock.adobe.com
January is right in the middle of winter for the Northern Hemisphere, which is the coldest season of the year and generally sees the lowest temperatures and highest chances of snowfall. No snow will be falling in San Diego in January, but this is one of the two coldest months of the year in the city, along with December. January’s average temperatures in San Diego tend to hover around 57 °F (14 °C), which is quite mild compared to many other major United States cities, but still not suitable for shorts and T-shirts.
In January, San Diego’s average high temperatures are around 66 °F (19 °C), while the average lows can be approximately 49 °F (9 °C). This means that at the warmest times of the month, the conditions are quite comfortable, but it can get very chilly as well in a typical January day. In general, January’s weather conditions in San Diego are mild enough for people to go outside, but not very well-suited for many outdoor activities.
The average temperatures in January for San Diego tend to start off quite low and get progressively higher over the course of the month. January 1, for examples, has an average daily temperature of 55 °F (13 °C), whereas January 31 at the end of the month has an average temperature of 61 °F (16 °C), so if you want to enjoy slightly warmer temperatures, it makes sense to visit towards the end of January.
Regarding rainfall, January is among the wettest months of the year in San Diego. The city is immensely dry in the summer but can get very wet in the winter months, with January, February, and December seeing the highest amounts of precipitation on average. Around 48mm of rain falls in January in San Diego, with six rainy days occurring in this month.
The final weather factor to consider in January for San Diego is the amount of daylight the city gets. This is actually one of the darkest months of the year for San Diego, with only seven hours of sunshine on average each day. The previous month of December has eight hours per day, while the following month of February also has eight.