San Onofre State Beach • Statistics for April

April: More Swell, Less Grooming

April is a tale of two factors: the swell itself is actually quite good, but the wind is increasingly marginal. Average swell height remains at 3.6ft (1.1m), while the period climbs to a very respectable 13.3s. The directional distribution is excellent for San Onofre: WSW leads at 41%, W drops to 33%, SW is 22%, and SSW contributes 4%. This is one of the highest percentages of directly favorable southwest swell of the year. Significant wave energy falls into the 2-3ft (0.5-1m) and 3-5ft (1-1.5m) classes, with about 11% reaching the 5-8ft (1.5-2.5m) range.

The problem in April is the wind. Ideal conditions occur only 19% of the time, and onshore winds from the south and southwest are the dominant regime, totaling about 38% of observations. The daily W/SW sea breeze strengthens, frequently ruining the afternoon quality and leaving only a limited dawn patrol window. Water temperature dips to 13.9°C - the coolest of the season - while air temperatures rise to 15.5°C and rainfall drops to 0.66 mm/day. If you can find a morning with light north wind, April's SW swell can produce lined-up, rippable waves.