National Network of Regional Coastal Monitoring Programmes

Note that these are real-time data and are not quality-controlled. Long-range graphs are plotted from a randomised subsample of half-hourly data.

St Mary's Sound

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(i) stands for Iridium

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Sea and Swell Summary for (31/03/2025 23:30(i) GMT)
Significant Wave Height (m)	1.57
Wave zero up crossing period (Spectrum Tz) (s)	4.1
Wind Wave Significant Wave Height (m)	1.54
Wind Wave Peak Period (s)	5.1
Wind Wave Peak Period Direction (°)	113
Swell Significant Wave Height (m)	0.31
Swell Peak Period (s)	10.5
Swell Peak Period Direction (°)	123.8
% Swell	3.9

Wave Spectra for date 31/03/2025 23:30(i):

Frequency (Hz)	Period (s)	Normalised Energy	Energy
0.055	18.2	0.009	0.019
0.075	13.3	0.042	0.092
0.095	10.5	0.051	0.111
0.115	8.7	0.036	0.078
0.135	7.4	0.032	0.069
0.145	6.9	0.071	0.155
0.155	6.5	0.126	0.275
0.165	6.1	0.206	0.451
0.175	5.7	0.522	1.144
0.18	5.6	0.58	1.27
0.185	5.4	0.979	2.146
0.19	5.3	0.778	1.704
0.195	5.1	1	2.191
0.2	5	0.715	1.567
0.205	4.9	0.811	1.777
0.21	4.8	0.617	1.353
0.215	4.7	0.5	1.096
0.225	4.4	0.249	0.546
0.235	4.3	0.201	0.441
0.245	4.1	0.289	0.633
0.255	3.9	0.115	0.252
0.275	3.6	0.185	0.405
0.295	3.4	0.128	0.281
0.315	3.2	0.073	0.159
0.335	3	0.087	0.19
0.415	2.4	0.028	0.061
0.495	2	0.02	0.044