St Mary's Sound wave buoy daily means for Apr 2026

Daily means from the St Mary's Sound wave buoy for Apr 2026, including available wave height, period, direction, wind and sea temperature data.

Last observation shown Thu, Apr 30, 2026, 23:30

Data available: Sun, Jul 3, 2016 to Sat, Aug 22, 2026

Monthly means for 2026

Period Summary

Hog Says

1,426 wave-buoy observations covered all 30 days. Typical wave height was 4.6 ft (10th–90th percentile 2.1–8.5 ft), while the reported wave period averaged 5.3 seconds (10th–90th percentile 4–6 seconds). Mean water temperature was 11.3°C (10th–90th percentile 11–11.6°C). All 5,704 checked values passed quality control. Across 9 comparable years, mean wave height was above the same-month mean of 3.8 ft and mean wave period was below the same-month mean of 6.7 seconds.

Generated only from the observations and comparisons shown on this page.

Typical Significant Wave Height

4.6ft

Mean: 5 ft

P10–P90: 2.1 — 8.5 ft

Recorded extremes

1.1 — 12.7 ft

Mean Observed Wave Period

5.3secs

P10–P90: 4 — 6secs

Recorded extremes

3 — 7secs

Observed Wave Direction

SSW

Circular concentration: 42%

Mean Water Temperature

11.3°C

P10–P90: 11 — 11.6°C

Recorded extremes

10.9 — 12.4°C

Compared With Previous Aprils

Historical baseline from 8,024 observations across 9 years.

Wave Height: 5ft; 1.2ft above mean; Historical mean 3.8ft
Wave Period: 5.3s; 1.4s below mean; Historical mean 6.7s
Water Temperature: 11.3°C; 0.5°C above mean; Historical mean 10.8°C

Show 10th–90th percentile ranges

About St Mary's Sound wave buoy

St Mary's Sound station lies between St Mary's and St Agnes in the Isles of Scilly. The National Network first deployed a Datawell Directional WaveRider here in May 2014, establishing a nearshore record for an archipelago exposed to Atlantic swell and important to local navigation and coastal management.

Its current data source reports wave height, wave period, wave direction, directional spread and sea temperature.

St Mary's Sound wave buoy daily means Apr 2026Last observation shown Apr 2026
Metric	Apr 1	Apr 2	Apr 3	Apr 4	Apr 5	Apr 6	Apr 7	Apr 8	Apr 9	Apr 10	Apr 11	Apr 12	Apr 13	Apr 14	Apr 15	Apr 16	Apr 17	Apr 18	Apr 19	Apr 20	Apr 21	Apr 22	Apr 23	Apr 24	Apr 25	Apr 26	Apr 27	Apr 28	Apr 29	Apr 30
Mean significant wave height (ft)	2	3	4	6	5	5	6	4	QC rejected	5	7	6	4	5	7	6	5	3	2	4	10	10	7	7	4	2	2	3	7	6
Mean maximum wave height (ft)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Mean peak period (s)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Mean zero-crossing period (s)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Mean reported period (s)	5	5	5	5	6	5	5	6	5	5	6	6	5	5	5	6	5	6	5	4	6	6	5	5	6	6	4	4	5	5
Mean peak wave direction	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Mean directional spread (°)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Mean reported wave direction	Wconcentration 56%	WNWconcentration 67%	WSWconcentration 81%	SWconcentration 90%	WSWconcentration 87%	SSEconcentration 82%	SEconcentration 71%	WSWconcentration 76%	Wconcentration 89%	Wconcentration 35%	SWconcentration 96%	WSWconcentration 97%	WSWconcentration 86%	SSWconcentration 97%	SSWconcentration 98%	SWconcentration 94%	SWconcentration 83%	Wconcentration 85%	Wconcentration 62%	ESEconcentration 95%	ESEconcentration 99%	ESEconcentration 100%	ESEconcentration 89%	SSEconcentration 70%	SWconcentration 100%	SWconcentration 100%	SWconcentration 54%	Econcentration 80%	Econcentration 100%	Econcentration 97%
Mean water temperature(°C)	11.0	11.0	11.0	11.0	11.0	11.1	11.1	11.2	11.2	11.2	11.1	11.0	11.1	11.1	11.2	11.2	11.3	11.3	11.3	11.3	11.3	11.3	11.3	11.3	11.5	11.5	11.7	11.8	11.7	11.8

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Observation data source

Regional Coastal Monitoring Programme

Learn how SurfHog combines, checks and summarizes observations in the data and methodology notes.

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