Waves in St Mary's

Hourly wave forecast for 7 days · updated today, Wednesday, October 28, at 9:59 pm (GMT)

Now · significant height 8.1 ft

Sea state: Moderate · Douglas 4
Period: 10.1 s · W
Swell: 7.7 ft · 9 s
Highest expected: 16 ft

Waves up to 14 ft today

Today the sea at St Mary's is moderate: 8.1 ft waves with a period of 10.1 s from the west. The swell, 7.7 ft at 9 s, comes from the west.

Wave height, next 7 days

5.01015 ft 14 ft Now

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 common4.1 ft
Significant8.1 ft
Highest expected16 ft

One wave in seven is higher than the significant height, and about 3 times a day one reaches 16 ft. Before heading out, expect waves of up to 16 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	1.6 ft–4.1 ft
4	Moderate · today	4.1 ft–8.2 ft
5	Rough	8.2 ft–13.1 ft
6	Very rough · week peak	13.1 ft–19.7 ft
7	High	19.7 ft–29.5 ft
8	Very high	29.5 ft–45.9 ft

Waves day by day

Day	Max wave	Sea state	Direction	Max period	Swell	Max wind
Today	14 ft	Very rough	W	11 s	13 ft W	21 mph SW
Thu 29	7.7 ft	Moderate	WSW	10 s	6.8 ft W	23 mph SSE
Fri 30	6.9 ft	Moderate	WSW	11 s	6.5 ft W	21 mph SE
Sat 31	6.9 ft	Moderate	W	10 s	6.5 ft W	14 mph E
Sun 1	5.8 ft	Moderate	WNW	10 s	5.1 ft W	11 mph NE
Mon 2	5.1 ft	Moderate	NE	8 s	3.5 ft W	16 mph ENE
Tue 3	5.4 ft	Moderate	E	8 s	3.3 ft E	16 mph ENE

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	14 ft	13 ft	13 ft	12 ft	11 ft	9.9 ft	9.1 ft	8.3 ft
Period	11.2 s	11.3 s	11.4 s	11.1 s	10.8 s	10.6 s	10.4 s	10.2 s
Direction	W	W	W	W	W	W	W	W
Swell	13 ft · 10 s	13 ft · 10 s	12 ft · 10 s	11 ft · 10 s	11 ft · 9 s	9.8 ft · 9 s	9.0 ft · 9 s	8.2 ft · 9 s
Wind (mph)	21 WSW	17 WSW	19 WSW	18 WSW	15 WSW	11 SW	8 S	10 S

Previous days

The waves over the last 14 days. Tap a day to see it hour by hour.

Day	Max wave	Period	Swell
Tue 27	16 ft WSW	11 s	14 ft WSW
Mon 26	15 ft WSW	10 s	9.8 ft W
Sun 25	18 ft W	11 s	13 ft W
Sat 24	18 ft W	10 s	9.8 ft WNW
Fri 23	21 ft W	12 s	21 ft WSW
Thu 22	19 ft WSW	11 s	11 ft W
Wed 21	16 ft W	10 s	6.9 ft W

Show all 14 days

Day	Max wave	Period	Swell
Tue 20	10 ft W	12 s	5.9 ft WNW
Mon 19	5.6 ft N	12 s	4.6 ft NW
Sun 18	4.9 ft N	9 s	3.9 ft NNW
Sat 17	7.9 ft WNW	10 s	6.9 ft W
Fri 16	11 ft W	11 s	10 ft W
Thu 15	12 ft W	12 s	11 ft W
Wed 14	9.2 ft W	10 s	8.2 ft W

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 St Mary'sQuestions

How are the waves today in St Mary's?

Moderate (8.1 ft with a period of 10.1 s from the west). The highest wave to expect is around 16 ft.

Which day will have the biggest waves this week?

Wednesday 28, with waves up to 14 ft (very rough).

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 16 ft.

More about St Mary's today

Waves near St Mary's

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 2.9 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 9:59 pm (local time).

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