Good Rats - surf spot statistics

Best Surf Season (November - March)

The North Atlantic roars to life during these months, delivering the most consistent and powerful swell to Good Rats. Average wave heights range from 2.5m to 3.0m with long periods averaging 11-12 seconds, thanks to a steady parade of extratropical cyclones tracking across the basin. Swell directions are dominated by the optimal WSW, SW, and SSW, perfectly aligned with the beach's SW exposure. Offshore winds from the NE and ENE quadrant blow a higher percentage of the time, especially from December through February, when the polar jet stream strengthens and the NAO often dips negative, driving storm tracks closer to the coast. This combo produces clean, grinding, long-period surf that can hold a board comfortably. The main challenge is the occasional onshore flow from the SE and S when high-pressure systems set up to the east, but overall, this is prime time for the spot.

Fair Surf Season (April & October)

These shoulder months offer a transition between the winter peak and summer lull. April still sees respectable average wave heights of 2.2m and periods around 10.8s, with a high percentage of ideal wind (39%) – the highest of any month. However, the swell becomes more inconsistent as the storm track shifts north. October sees a resurgence with 2.5m average height and 10.4s period, but the wind ideal rate drops to 29%, meaning more variable conditions. Both months benefit from a mix of groundswell and windswell, and with the right setup – a low pressure passing to the north and a cold front clearing out – you can score fun, punchy surf with clean offshore breezes.

Low Surf Season (May - September)

Summer settles in, and Good Rats goes into a slumber. Average wave heights drop to 1.3-1.7m, with periods shrinking to 9-10 seconds. Swell still comes from the preferred SSW-SW-WSW directions, but the energy is often weak and short-period, producing mostly small, mushy, or choppy waves. The biggest enemy is the wind: onshore flow from the SSW, SW, and WSW becomes predominant, especially from June through August, when ideal wind percentages bottom out at 19-24%. Afternoon seabreezes further degrade conditions. A stray tropical storm or cloud-to-ground hurricane swell can briefly light things up in September, but consistency is low. For the dedicated surfer, a groveler or longboard is the board of choice on the rare clean dawn patrol with a light offshore breeze from the north or east.

October: The Real Return

October is when the North Atlantic wakes up in earnest. The average swell height climbs to 2.5m with a period of 10.4s, signaling the return of consistent groundswell. Swell directions are squarely in the optimal range: WSW (19.9%), SW (16.7%), and SSW (8.3%). These are generated by the first cold-season lows moving off the coast, often deepening rapidly. Wind conditions are still transitional: the ideal wind percentage is only 29%, with SE (11.1%), SSE (12.2%), and S (9.8) winds blowing onshore many days. But the increasing frequency of cold fronts brings more frequent NW and NNW winds behind them, clearing out the air and grooming the swell. When a high-pressure system settles over New England following a low, you get classic fall perfection: glassy conditions with chest-to-head-high, long-period waves that offer great shape. October can deliver some of the best sessions of the year for those willing to watch the charts and time the post-frontal window.