Grumari • Surf Spot Statistics

Best Surf Season (May - August)

Grumari is a place that lives and dies by the South Atlantic storm track. Its SSE-facing beach is wide open to the swell-producing ESE, SE, SSE and S quadrants, while still getting shelter from the messy west/northwest windswell that puts other spots to work. From May through August, the ocean gets properly organised. Average wave heights hold in the 4ft (1.2m) range, periods stretch to 10.8-11.1s, and the share of clean offshore wind from the N, NW, WNW and NNW directions reaches its annual maximum at 47-55%. June is the standout with 55% ideal wind, an 11.1s average period and a healthy mix of S and SSW groundswell that lines up into the bay. The dry autumn and winter airmass, with rainfall dropping below 2.5mm per day, also keeps the surface glassier and the sandbars more settled.

Fair Surf Season (March - April, September - October)

The transition months are a game of trade-offs. In March and April, average size climbs from 3ft (0.9m) to 4ft (1.2m), and period gradually increases to 10.4-10.6s while ideal wind still happens around 43% of the time. September and October see the tail end of winter swell, with 3.5-4.3ft (1.1-1.3m) waves and solid period, but the return of the South Atlantic trade winds cuts ideal wind down to 31-37%. You can still score, but you have to pick your windows carefully and hunt for mornings when the N/NW offshore flow beats the afternoon onshore seabreeze.

Low Surf Season (November - February)

Austral summer is Grumari's slow season. The mid-latitude storm track weakens and shifts south, average wave heights drop to 3-3.5ft (0.9-1.1m), and periods fall to 9.6-9.9s. Much of the swell that arrives is shorter-period ESE/SE windswell generated by the NE trade winds, and the summer rainy season adds frequent onshore wind and lumpy, rain-affected surfaces. There are still fun, groveling 2-4ft days, especially when a rare winter-like low sneaks up the coast, but consistency and power are at their lowest. If you have one trip window, aim for June or July.