Sea Crossings
State of Sea until 1800 Wednesday 21 January 2026
Dublin - Holyhead
Slight to moderate. Increasing moderate to rough on Tuesday morning.
Rosslare - South Wales
Slight to moderate. Increasing moderate to rough Tuesday morning and very rough for a time on Tuesday evening and night.
Cork - South Wales
Slight to moderate. Increasing moderate to rough Tuesday morning and very rough for a time on Tuesday evening and night.
Rosslare - France
Moderate to rough. Increasing rough to very rough Monday evening.
Cork - France
Moderate to rough. Increasing rough to very rough Monday evening.
Rosslare - Spain
Moderate to rough. Increasing rough to very rough on Monday evening, and possibly increasing high at times through Tuesday.
Legend
| Sea Crossings | WMO Code | Wave height | Characteristics |
|---|---|---|---|
| 0 | 0 metres (0 ft) | Calm (glassy) | |
| 1 | 0 to 0.1 metres (0.00 to 0.33 ft) | Calm (rippled) | |
| 2 | 0.1 to 0.5 metres (3.9 in to 1 ft 7.7 in) | Smooth (wavelets) | |
| 3 | 0.5 to 1.25 metres (1 ft 8 in to 4 ft 1 in) | Slight | |
| 4 | 1.25 to 2.5 metres (4 ft 1 in to 8 ft 2 in) | Moderate | |
| 5 | 2.5 to 4 metres (8 ft 2 in to 13 ft 1 in) | Rough | |
| 6 | 4 to 6 metres (13 to 20 ft) | Very rough | |
| 7 | 6 to 9 metres (20 to 30 ft) | High | |
| 8 | 9 to 14 metres (30 to 46 ft) | Very high | |
| 9 | Over 14 metres (46 ft) | Phenomenal |
