San Onofre State Beach • Statistics for January

January: The Winter Window

The North Pacific delivers its most consistent groundswell of the season in January, and San Onofre sits right in the firing line for west-southwest energy. The average swell height checks in around 3.3ft (1.0m) with a 12.6s period, which is the kind of long-period pulse that actually wraps into the cove and holds its shape. The swell distribution is heavily weighted toward the W (63%) and WSW (25%) directions, with another 7% from the SW and a touch of SSW. The W component is a degree or two north of the absolute optimal window, but the large percentage of WSW/SW energy means plenty of waves will be hitting the beach correctly. Heights are mostly split between 2-3ft (0.5-1m) and 3-5ft (1-1.5m), with a healthy 7% sneaking into the 5-7ft (1.5-2m) range - that is proper pumping San O.

On the wind side, January is the cleanest month of the year alongside December. Winds are ideal for surfing 53% of the time, with the offshore quadrant from N to ENE accounting for over a third of all wind observations. Morning offshore/drainage winds, often out of the NNE and NE, groom the lines and keep the surface glassy before the afternoon sea breeze develops. Bad, south-southwest through WSW winds only total about 17%, a low enough number to keep the month mostly workable. Air temperatures average 13.2°C and the water temperature sits at 14.1°C in a winter wetsuit. With 2.35 mm/day of precipitation, passing frontal systems are the engine; when the sky clears behind one, the combination of fresh W/WSW groundswell and offshore NE flow is as good as San Onofre gets.