Grumari - surf spot statistics

Grumari, Brazil, offers surfable conditions year-round, but the best months for consistent surf are typically from April to July. During this period, ground swell frequency peaks (51-58%), providing cleaner, more organized waves, while wind swell remains moderate (41-52%). Mean swell size also increases to around 1.5-1.6m, offering better wave power. Wind conditions during these months are not ideal but manageable, with 25-30% of days having favorable offshore or light winds, though onshore winds dominate. The worst wind conditions occur from August to November, where unfavorable winds exceed 80% of days, often causing choppy surf despite decent swell. From December to March, wind swell dominates (63-69%), resulting in less consistent wave quality, though still surfable, especially when ground swell contributes. September stands out with the largest mean swell (1.7m) but suffers from the highest percentage of bad winds (85%). For the best balance of swell size, ground swell dominance, and less terrible wind conditions, May and June are the top months—offering a solid mix of wave energy and occasional clean conditions. Early mornings or late evenings may provide better surf due to lighter winds. Overall, intermediate to advanced surfers will find the most rewarding sessions in late autumn and early winter (April-July), while other months require patience with wind and swell variability.

In October, Grumari offers surfers moderate but decent conditions with an average swell height of **1.6m** and a solid **9.7s period**, providing well-formed, punchy waves suitable for intermediate to advanced surfers. The dominant swell directions are **E, ESE, SE, SSE, and S**, with the majority of waves falling in the **1-2.5m range**—enough power for turns and maneuvers while remaining manageable. The **best waves come from the east to south-southeast**, as they align best with the break, offering cleaner, more organized faces. Wind conditions are a mix, with only **15% of days providing ideal offshore winds** (likely light NNE to NW winds early in the day before sea breezes kick in). The most frequent winds are **ENE to ESE at 10-30kph**, which can create some chop, especially in the afternoons. However, mornings often have lighter winds, making dawn patrols the best bet for glassy conditions. Overall, October is a **fairly reliable month** at Grumari, with consistent swells and occasional clean days, though wind interference means timing sessions around the early hours or waiting for favorable wind shifts is key. The wave quality is best when the swell direction avoids being too southerly, as it can lead to inconsistency, while easterly swells tend to wrap better into the bay.