Sumner Avenue • Surf Spot Statistics

Best Surf Season (September - March)

Sumner Avenue's south-southeasterly orientation means the prime surf window opens when the Atlantic starts to deliver both proper swell and the northwesterly offshore winds that groom it. From September through March, average surf heights range from 1.2 to 1.4m (4 to 4.6ft) and the average period climbs from 7 to 8.4s. This is when the storm track is active: strong extratropical cyclones and occasional tropical systems send S, SSE, SE and ESE swell into the coast, while cold fronts and high pressure bring W/NW/N winds. The NAO phase can magnify this, with negative phases often parking coastal lows and directing a clean northwesterly flow over the beach. The result is clean, punchy waves on a stretch of coast that is ultra-sensitive to onshore flow. Though winter water temperatures are brutal (3.9-8.7°C / 39-48°F), the quality and consistency are worth it.

Fair Surf Season (April - May)

Spring is transitional. Sea surface temperatures climb into the 9-14°C (48-57°F) range, and S/SE swells are still frequent, but the wind regime flips increasingly to SSW/SW onshore flow. Average heights ease to 1.1-1.2m (3.5-4ft) and the longer period groundswells become less common. Surfing is still possible, especially on days when a stubborn NW high slips in, but expect more wind-affected, lumpy conditions.

Low Surf Season (June - August)

Summer is the low season at Sumner Avenue. Average swell height drops to just 0.9m (3ft), periods sit near 7s, and the dominant S/SE swell is mostly short-period windswell driven by the Bermuda High. The same ESE/SE/SSE/S directions that produce the swell also deliver the onshore wind, so surface conditions are often chopped and sectiony. Occasional tropical waves and late-season hurricane swells can light up August, but consistency is lacking.