Half Moon Bay weather in January
January in Half Moon Bay: cool, rainy, with muggy air — a fair time to visit.
Updated September 2026 · climate normals from ERA5 reanalysis
#11 of 12 months in Half Moon Bay · #1022 of 1413 destinations to visit in January · comfort 57/100 (tier D)
- Days
- 14°C
- Nights
- 7°C
- Wet days
- 10
- Sun
- 7.2 h
- Humidity
- 77%
- Daylight
- 10 h
Traveller notes on Half Moon Bay in January
No notes yet. Open Half Moon Bay on the map to add the first one.
Half Moon Bay climate normals — January
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Half Moon Bay in January
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusyWinter / Christmas break in United States, school holidays in 2 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Half Moon Bay's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Toughest weatherHalf Moon Bay's weather peaks July–September.
Best weatherFair weatherToughest weather
Nearby, and something's on
Within 300 km of Half Moon Bay — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Half Moon Bay?
Half Moon Bay in January — FAQ
- Is January a good time to visit Half Moon Bay?
- January in Half Moon Bay: cool, rainy, with muggy air — a fair time to visit. It ranks #11 of 12 months for Half Moon Bay on SeasonMap's comfort score (57/100).
- What is the weather like in Half Moon Bay in January?
- In January, Half Moon Bay averages a daily high of 14.3°C and a low of 7.3°C, with about 123.8 mm of rain over roughly 10 rainy days.
- What is the air quality in Half Moon Bay in January?
- Half Moon Bay has a mean US Air Quality Index of about 51 in January.
Within 300 km: San Francisco's Plum and magnolia blossom around 25 Jan – 15 Mar, and Santa Cruz, California's Monarch butterflies around 15 Oct – 15 Feb.