Bathtub Beach • Statistics for September

September: Tropical Swell Comeback

September is the hinge month between summer smallness and winter consistency. Average surf heights jump back to 3ft (1.0m) and periods stretch to 8.2s, driven mostly by a dramatic increase in NE and ENE swell, which account for 31.6 and 30.3 percent of the wave directions. The downside is that wind quality remains poor: only 19 percent offshore, while ENE and E winds blow 15.0 and 13.7 percent of the time. Onshore easterlies still plague the beach for much of the month, but the arrival of a hurricane or a strong extratropical low can quickly flip the script. Water temperature is at its yearly peak around 28.4°C, air temps average 27.6°C, and rainfall is high at 6.50 mm/day. When the right tropical storm system aligns, September can deliver the first seriously pumping waves since spring.