Horseshoe • Statistics for December

December: Winter Swell Machine

December delivers the first true winter swell push of the year. The average swell height reaches 5ft (1.6m), the period holds at an excellent 10.0s, and the NE monsoon machine is running at full blast. The swell is overwhelmingly from NE (60.1%) and ENE (24.8%), with modest NNE input at 7.9%. More importantly, the height distribution is stacked: 27.5% of observations are in the 3-5ft (1-1.5m) range, 23.5% in the 5-6ft (1.5-2m) range, and even 7.4% above 6ft (2m). For an east-facing spot, this is the most sustained period of rideable, powerful surf of the year - if the wind ever plays ball.

Unfortunately, the winter wind pattern is punishing. ENE 24.9%, NE 18.5%, E 15.5%, and ESE 8.8% combine for a mostly cross-onshore setup, and ideal wind sits at only 5%. The waves will frequently be bumped up and hard to read. The trick is to time the short-lived offshore windows, usually at dawn, or when a cold surge in the South China Sea drags the wind into the NW/W quadrant. Water remains a warm 28.4°C, air temps are 27.7°C, and rainfall jumps to 14.8mm/day. Big surf is on the menu, but it's served with a side of monsoon chop.