Verdict: Excellent month
San Diego Weather in January
January is mild-to-cool in San Diego, topping out near 17°C (63°F) — comfortable with a layer on. Rain is occasional — about 7 wet days in a typical year. Overall, January is one of the best months of the year to be in San Diego.
Average high
17°C / 63°F
Average low
8°C / 46°F
Rain days
~7
Precipitation
71 mm
What to pack for San Diego in January
- Layers — t-shirts under a light jacket or sweater
- Evenings turn genuinely cool — pack a warm layer for after dark
- A packable rain shell or compact umbrella earns its space
- Comfortable walking shoes — every guide on this site assumes you'll use them
January against the rest of the year
Warmest in San Diego: Aug (26°C / 79°F) · Coolest: Jan (17°C / 63°F) · Wettest: Mar (~10 rain days)
17°
8°
Jan
18°
8°
Feb
17°
10°
Mar
19°
12°
Apr
20°
14°
May
22°
16°
Jun
24°
18°
Jul
26°
19°
Aug
25°
18°
Sep
24°
15°
Oct
21°
11°
Nov
18°
9°
Dec
Daily highs / lows in °C · bars show rain days per month · ERA5 climate normals (2020–2024)