Waves in Half Moon Bay
Hourly wave forecast for 7 days · updated today, Thursday, October 29, at 12:03 pm (GMT+13)- Sea state
- Slight · Douglas 3
- Period
- 3.0 s · WNW
- Swell
- 0.5 ft · 4 s
- Highest expected
- 3.8 ft
Today the sea at Half Moon Bay is slight: 1.8 ft waves with a period of 3.0 s from the west-northwest. The swell, 0.5 ft at 4 s, comes from the north. Biggest waves: Wednesday 4, with waves up to 3.7 ft (slight).
Wave height, next 7 days
Significant height: the average of the highest third of the waves, what an observer would estimate by eye. Swell: waves arriving from far away, longer.
The waves you may find today
- Most common0.9 ft
- Significant1.8 ft
- Highest expected3.8 ft
One wave in seven is higher than the significant height, and about 3 times a day one reaches 3.8 ft. Before heading out, expect waves of up to 3.8 ft.
The Douglas sea state scale
| Degree | Name | Wave height |
|---|---|---|
| 0 | Calm (glassy) | 0 |
| 1 | Calm (rippled) | 0.0 ft–0.3 ft |
| 2 | Smooth | 0.3 ft–1.6 ft |
| 3 | Slight · today | 1.6 ft–4.1 ft |
| 4 | Moderate | 4.1 ft–8.2 ft |
| 5 | Rough | 8.2 ft–13.1 ft |
| 6 | Very rough | 13.1 ft–19.7 ft |
Waves day by day
| Day | Max wave | Sea state | Direction | Max period | Swell | Max wind |
|---|---|---|---|---|---|---|
| Today | 2.2 ft | Slight | WNW | 3 s | 0.6 ft N | 19 mph W |
| Fri 30 | 2.4 ft | Slight | WSW | 3 s | 0.6 ft N | 23 mph WSW |
| Sat 31 | 1.8 ft | Slight | SSW | 3 s | 0.4 ft S | 15 mph SSW |
| Sun 1 | 2.0 ft | Slight | NNE | 7 s | 0.9 ft NE | 11 mph NNE |
| Mon 2 | 2.9 ft | Slight | NNE | 4 s | 1.5 ft NNE | 13 mph N |
| Tue 3 | 2.0 ft | Slight | NNE | 5 s | 1.5 ft NNE | 11 mph NNE |
| Wed 4 | 3.7 ft | Slight | NE | 5 s | 1.2 ft NNE | 12 mph NE |
Today, every 3 hours
| Time | 12:00 am | 3:00 am | 6:00 am | 9:00 am | 12:00 pm | 3:00 pm | 6:00 pm | 9:00 pm |
|---|---|---|---|---|---|---|---|---|
| Waves | 1.3 ft | 1.2 ft | 1.1 ft | 1.4 ft | 1.8 ft | 2.1 ft | 2.1 ft | 1.8 ft |
| Period | 3.1 s | 3.1 s | 3.1 s | 2.9 s | 3.0 s | 3.1 s | 3.2 s | 3.1 s |
| Direction | WNW | NW | NW | WNW | WNW | WNW | WNW | W |
| Swell | 0.6 ft · 5 s | 0.6 ft · 5 s | 0.5 ft · 5 s | 0.5 ft · 5 s | 0.5 ft · 4 s | 0.5 ft · 4 s | 0.5 ft · 5 s | 0.5 ft · 4 s |
| Wind (mph) | 7 W | 7 W | 6 WNW | 14 W | 17 W | 18 W | 16 W | 13 W |
Previous days
The waves over the last 14 days. Tap a day to see it hour by hour.
| Day | Max wave | Period | Swell |
|---|---|---|---|
| Wed 28 | 1.6 ft NW | 6 s | 1.0 ft NNE |
| Tue 27 | 2.6 ft NW | 4 s | 1.6 ft NNE |
| Mon 26 | 1.3 ft NNW | 6 s | 0.7 ft NNE |
| Sun 25 | 0.3 ft NNE | 6 s | 0.3 ft NNE |
| Sat 24 | 0.3 ft NNE | 7 s | 0.3 ft NNE |
| Fri 23 | 1.0 ft S | 7 s | 0.3 ft SE |
| Thu 22 | 1.0 ft SSW | 7 s | 0.3 ft ENE |
Show all 14 days
These are the models at the start of each day (ECMWF and GFS; waves from Météo-France), not readings from a weather station: there can be differences at specific spots.
Questions about the waves in Half Moon BayQuestions
How are the waves today in Half Moon Bay?
Slight (1.8 ft with a period of 3.0 s from the west-northwest). The highest wave to expect is around 3.8 ft.
Which day will have the biggest waves this week?
Wednesday 4, with waves up to 3.7 ft (slight).
What is the wave period?
The time, in seconds, between two crests. With long periods (over 10 s) waves come from far away, are cleaner and break harder; with short periods they are wind waves, choppier.
What is significant wave height?
The average of the highest third of the waves. One in seven is higher and, a few times a day, one comes in at almost double: today, about 3.8 ft.
More about Half Moon Bay today
Waves near Half Moon Bay
Only places with a different forecast: spots a few miles apart share the same model cell and wouldn't add anything.
Learn more
Waves: Open-Meteo with Météo-France (MFWAM, up to 10 days) and ECMWF WAM, CC BY 4.0; wave grid point 12 mi away. Near the shore, the seabed and the shape of the coast change the waves.
Forecast from Open-Meteo (CC BY 4.0) with models from ECMWF, NOAA, Météo-France, DWD, Copernicus Marine and CAMS. Updated at 12:03 pm (local time).
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