Santa Maria • Statistics for December

December: Peak Size and Peak Trade Wind Stress

December marks the apex of the winter swell window. The average swell height is 1.9m (6ft) and the period is an impressive 11.0s, with a swell spectrum that is broader than midwinter: NNE 35.8%, NNW 22.2%, N 14.6%, NE 15.5%, and even a small ENE component (1.0%). A full 17.0% of NNE swells and 11.3% of NNW swells are in the 1.5-2m (5-6ft) range, with 10.5% and 5.6% respectively in the 2-2.5m (6-8ft) class - this is the most powerful month for push, even if the direction is not ideal. The catch is wind. NE dominates with 59.6% and ENE adds 20.8%, resulting in an offshore wind window of just 10%. Water temperature has cooled to 24.4°C, air to 23.3°C, rainfall at 0.96 mm/day. For the surfer chasing size above all, December is it; but you'll need patience and a favourable NW/NNW wind shift to make the most of it.