Half Moon Bay weather by month
The best time to visit Half Moon Bay is July to September — 87/100 in September, 22°C and 3 rainy days. The best season is summer, June to August (84/100 on average).
The worst month is December at 50/100 — cool, soaked, muggy air. See December →
Updated September 2026 · climate normals from ERA5 reanalysis
Planning the wider trip? Best time to visit United States →
Best season: June to August (84/100 on average) · worst December (50/100)
- Days
- 22°C
- Nights
- 13°C
- Wet days
- 3
- Sun
- 11 h
- Humidity
- 83%
- Daylight
- 12 h
Half Moon Bay, month by month
Comfort score out of 100 for the kind of trip Half Moon Bay is best for, the average high, rainy days and hours of sun a day from the climate normals, and how busy it tends to be.
Crowds in Half Moon Bay in September
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.
BusySummer break in United States(estimated)
Peak crowdsBusyShoulder seasonQuiet