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 May, Grumari offers fairly consistent surf conditions with an average swell height of 1.6m and a solid average period of 10.9s, indicating clean and well-organized waves. The swell distribution shows that the majority of waves come from southerly directions (S, SSE, and SE), with heights most frequently in the 1-2.5m range, providing good surfable waves. The highest probability for quality waves is from the S direction, where 1.5-2.5m waves occur frequently, and there’s even a small chance of overhead surf (over 2.5m). Winds are favorable for surfing 29% of the time, with the best conditions typically coming from lighter easterly or southerly breezes, reducing onshore chop. Stronger winds, particularly from ENE to SE, can occasionally disrupt conditions, but overall, May delivers decent surf with a mix of mid-sized, clean waves and occasional offshore wind assistance. A solid month for intermediate to advanced surfers.