Osbourne • Statistics for December

December: Winter Sets In

December closes the year with maximum average swell size at Osbourne: 5-6ft (1.7m) and an average period of 8.6s. The dominant swell directions are SSW (14.7 percent) and SW (12.2 percent), with S (10.2 percent) and WSW (6.6 percent) also providing substantial mid-period energy. The most favourable E-ESE-SE-SSE sector contributes around 20 percent of the total, so much of the large winter swell is arriving from a southern quadrant and may hit Osbourne less directly. Still, the wind data is strongly offshore: WNW (14.2 percent), NW (13.4 percent), NNW (11.1 percent), and W (10.4 percent) dominate the surface flow, giving the spot a 24 percent chance of ideal wind conditions. The problem is the cold: water temperature plunges to 5.6°C and the average air temperature is just 1.9°C, with precipitation reaching 4.10 mm/day. December is a raw, powerful month for the committed local crew-when a big NNE-tracked storm aligns with a nortwesterly outflow, Osbourne can serve up some of the heaviest, most authenic winter waves of the year.