Praia Grande • Statistics for December

December: Winter's Crown Jewel

December may be the best month on the calendar for consistent, high-quality surf. The average wave height is 8.2ft (2.5m), tied with February for the winter peak, and the average period is a robust 12.7 seconds. The swell distribution is ideal, with NW at 21.2 percent, WNW at 15.2 percent, NNW at 11.3 percent, and W at 6.1 percent. Additional west-southwest and southwest energy appears occasionally, but the core of the swell is exactly where a west-northwest beach wants it. The defining feature of December is the wind: it is the only month with 24 percent ideal offshore flow, the highest of the year. The offshore quadrant - E, ESE, SE and SSE - is well represented, and these offshore days often coincide with high pressure over Iberia and crisp, dry air. NNW wind is reduced to 11.9 percent, N to 6.3 percent, and E to 8.9 percent, giving surfers real opportunities for morning - and sometimes all-day - clean conditions. Air temperatures average 12.3°C (min 0.9°C, max 19.6°C), precipitation is 2.69 mm/day, and water temperature is 15.4°C. For glassy winter surf, long-period NW groundswell and classic Portuguese beach breaks, December is hard to beat.