Llangennith • Statistics for January

January: Midwinter Power and the Atlantic Machine

January is the heart of the Llangennith season. The average swell height is around 5ft (1.6m) with a solid 10.7s period, and the dominant swell direction is unmistakably WSW, accounting for more than 39% of all swell energy. Add in W (18.3%), SW (8.1%) and WNW (4.6%), and the western quadrant delivers roughly 70% of the waves arriving on this west-southwest-facing beach. With periods in the 10-14s band, the waves are powerful, well-defined groundswell rather than windswell, and even the 3-8ft (1-2.5m) classes are well represented. The catch is the wind. Onshore W and WSW winds combine for around 20% of the surface flow, and the ideal offshore NE-ENE-E-ESE window is limited to only 9% of the time. When a strong winter low pushes across Iceland and the UK, Llangennith can hold big, thumping west swell, but it is often accompanied by stormy conditions. A cold frontal passage and a building high from the east is the golden ticket, producing offshore ENE-E winds that turn the beach into long, lined-up peaks. Water temperature is a chilly 8.4°C and air temperatures hover near 7°C, with 3.89mm/day of rain, so bring the thickest wetsuit you own and pick your windows carefully.