Cave Rock • Statistics for December

December: Micro Waves and Summer Wind

December brings the full summer doldrums to Cave Rock, including the lowest average wave period of the year (8.7s) and the lowest ideal wind frequency (15%). The swell height is still 1.6m (5.2ft), but that's misleading - most of that energy is short-period, wind-generated junk. The wind rose is overwhelmingly NE (23.8%), with SSW (18.0%) and NNE (10.7%) also present. Westerly offshore flow is a ghost: W 0.6%, WNW 0.5%, NW 0.4%, NNW 1.2%. The swell direction is dominated by E (18.6%), SSE (20.2%), SE (16.7%) and S (15.7%), but with the consistent NE wind blowing straight against the wave faces, the quality is poor. The 1-1.5m and 1.5-2m bands are most common, but the accompanying chop and crunch make it feel bigger and more chaotic than it is. Water temp is warm again at 24.1°C, air at 23.3°C, and rain is high at 3.69mm/day. For many, this is a time to swap the shortboard for a longboard or a warm-water session in the foam. The reef is still there, but you need a proper summer storm or a rogue SW groundswell to push through the trade wind mess - a rare occurrence indeed.