Sero Beach • Statistics for December

December: Monsoon Flow Returns with Cleaner but Smaller Surf

December marks the return of Sero Beach's best wind regime. Ideal conditions jump to 30 percent, and the offshore quadrant-NNW and NW especially-accounts for 25.4 percent of the wind. The trade winds have not fully died, with ESE and SE still over 21 percent combined, but the monsoon flow is clearly taking over. Average swell is 0.7m (2.3ft) with a 7.0s period, the smallest of the year, but the quality of the surf improves significantly once the wind goes offshore.

The swell spectrum becomes more varied again, with SSE at 57.5 percent and SE at 16.0 percent, plus a slot of W-WNW energy around 11.1 percent. Most heights are in the small-to-fun range: 37.7 percent of SSE swell sits in the 0.5-1m (1.6-3.3ft) class and 6.1 percent reaches 1-1.5m (3.3-4.9ft). Water temp warms to 28.6°C, air temps average 26.2°C and wet-season rain starts to build at 3.78mm/day. December is about clean, playful waves before the trade winds return; not big, but often perfect.