How warm is it in San Diego in January?

Daytime highs averaged 17.9 °C, night-time lows 9.0 °C. The highest value of the past 10 years was 27.3 °C (16 Jan 2021), the lowest 3.0 °C (23 Jan 2023).

How often does it rain in San Diego in January?

On average there were 6.7 rain days (at least 1 mm) with 57.7 mm of precipitation in total.

How warm is the sea in San Diego in January?

The sea temperature averaged 15.3 °C (open-sea point approx. 10 km from the town).

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San Diego weather in January: temperature & rain

Photo: Adbar · CC BY-SA 3.0

🇺🇸 Weather in San Diego in January

This is what the weather in San Diego (California, USA) was like in January over the years 2017–2026.

Key facts at a glance

Prevailing weather: Sunny

Avg. daytime high

17.9 °C

15.3 °C – 21.1 °C

Avg. night-time low

9.0 °C

8.0 °C – 11.4 °C

Avg. rain days in period

6.7

22 % of days · ≥ 1.0 mm

Avg. precipitation in period

57.7 mm

7.1 mm – 146 mm

Avg. cloud cover

52 %

This data source has no sunshine hours – average cloud cover is shown instead.

Avg. sea temperature

15.3 °C

Sea temperature available for 2 of 10 years.

Extremes: Highest temperature 27.3 °C (16 Jan 2021) · Lowest temperature 3.0 °C (23 Jan 2023) · Avg. daily peak wind 20 km/h

Weather mix of all days

94Sunny
87Partly cloudy
62Cloudy
37Light rain
29Rain
1Snow

Summary

On average 17.9 °C during the day and 9.0 °C at night.
On average 6.7 rain days (Rain day = at least 1.0 mm of precipitation) with 57.7 mm of precipitation in total.
The sea averaged 15.3 °C.
Prevailing weather: Sunny.
Warmest year: 2018 (avg. 21.1 °C), coolest: 2023 (avg. 15.3 °C).
Wettest year: 2023 (146 mm), driest: 2022 (7.1 mm).
Extremes: 27.3 °C on 16 Jan 2021 and 3.0 °C on 23 Jan 2023.

Overall values from all 10 years. How is this calculated?

Temperatures per year

Average over your travel period

Precipitation & rain days

Year by year

2026
Avg. max20.0°Avg. min10.5°
Rain days
5 Rain days
Precipitation
34.5 mm
Avg. cloud cover
48 % cloudy
Sea temperature
16.6 °C
Max 25.2 °C · Min 5.6 °C
2025
Avg. max17.6°Avg. min8.0°
Rain days
2 Rain days
Precipitation
14.3 mm
Avg. cloud cover
45 % cloudy
Sea temperature
14.0 °C
Max 24.0 °C · Min 5.2 °C
2024
Avg. max17.2°Avg. min8.8°
Rain days
7 Rain days
Precipitation
76.5 mm
Avg. cloud cover
54 % cloudy
Sea temperature
–
Max 23.2 °C · Min 3.6 °C
2023
Avg. max15.3°Avg. min8.0°
Rain days
14 Rain days
Precipitation
146 mm
Avg. cloud cover
59 % cloudy
Sea temperature
–
Max 20.2 °C · Min 3.0 °C
2022
Avg. max18.6°Avg. min9.0°
Rain days
3 Rain days
Precipitation
7.1 mm
Avg. cloud cover
48 % cloudy
Sea temperature
–
Max 22.4 °C · Min 3.7 °C
2021
Avg. max18.5°Avg. min9.0°
Rain days
8 Rain days
Precipitation
46.5 mm
Avg. cloud cover
48 % cloudy
Sea temperature
–
Max 27.3 °C · Min 3.8 °C
2020
Avg. max18.0°Avg. min8.7°
Rain days
4 Rain days
Precipitation
7.9 mm
Avg. cloud cover
48 % cloudy
Sea temperature
–
Max 21.8 °C · Min 6.0 °C
2019
Avg. max17.5°Avg. min8.6°
Rain days
8 Rain days
Precipitation
67.2 mm
Avg. cloud cover
54 % cloudy
Sea temperature
–
Max 23.0 °C · Min 3.0 °C
2018
Avg. max21.1°Avg. min11.4°
Rain days
3 Rain days
Precipitation
48.6 mm
Avg. cloud cover
57 % cloudy
Sea temperature
–
Max 26.3 °C · Min 5.4 °C
2017
Avg. max15.3°Avg. min8.2°
Rain days
13 Rain days
Precipitation
128 mm
Avg. cloud cover
56 % cloudy
Sea temperature
–
Max 22.4 °C · Min 3.2 °C

Frequently asked questions

How warm is it in San Diego in January?: Daytime highs averaged 17.9 °C, night-time lows 9.0 °C. The highest value of the past 10 years was 27.3 °C (16 Jan 2021), the lowest 3.0 °C (23 Jan 2023).
How often does it rain in San Diego in January?: On average there were 6.7 rain days (at least 1 mm) with 57.7 mm of precipitation in total.
How warm is the sea in San Diego in January?: The sea temperature averaged 15.3 °C (open-sea point approx. 10 km from the town).

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Data sources

Weather data: Data obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program
Reanalysis (weather model constrained by observations) on a coarse grid of about 50 km. Values represent a large area and can differ from local conditions, especially on islands, coasts and in mountains. Snow depth is the model value for the grid cell, not the depth on the slopes. No sunshine duration.
Reanalysis (weather model constrained by observations)
Reanalysis values represent a grid cell (approx. 25–50 km) and may differ from local measurements on coasts, islands and in mountains.
Sea temperature: MUR SST data were provided by JPL under support by NASA MEaSUREs program; accessed via NOAA CoastWatch ERDDAP
Daily multi-scale ultra-high resolution (≈ 1 km) analysis of satellite measurements (infrared, microwave) and in-situ data. Represents the foundation temperature below the daily warm surface layer. (Satellite and in-situ analysis); Sea measuring point approx. 10 km from the location (32.640, -117.200)
Place search: Natural Earth (public domain) · GeoNames (CC BY 4.0) / OpenStreetMap (ODbL)