Nahoon Reef • Statistics for September

September: Spring Swell Still Solid, Wind Quality Fades

September is a transitional month in the South African surf calendar. The ocean still carries winter-sized waves - averaging 2.1m - but the period shortens to 11.2s and the favourable-wind percentage drops to 26 per cent. Swell direction remains south-heavy, with SSW at 26.5 per cent and S at 16.3 per cent supplying most of the energy, while the E/ESE/SE/SSE quadrant improves to 31.8 per cent. There is still plenty of meat in the water: SSW shows 13.6 per cent at 1.5-2m and 10.4 per cent at 2-2.5m. The wind, however, starts to turn fickle once more. ENE at 11.6 per cent and NE at 16.1 per cent are back, and although WSW at 15.4 per cent and SW at 12.9 per cent remain present, the clean offshore windows of W/NW/NNW are less frequent than in mid-winter.

Air temperatures begin to climb to 18.4°C, water temperature holds at 19.2°C, and rainfall increases to 2.04mm/day. The surf is still good, but you have to pick the windows with more care as the synoptic pattern becomes more variable between summer and winter regimes.