Agua d'Alto in Portugal offers consistent surfable conditions year-round, but the best months for surfers seeking quality waves and favorable winds are from October to April. During this period, ground swell dominates (61-76% of the time), providing more powerful and organized waves, with mean swell sizes ranging from 2.1m to 2.7m—peaking in December at 2.7m. The winter months, particularly December through February, deliver the largest and most reliable surf, though wind conditions are less ideal, with bad onshore winds occurring 85-88% of the time. Conversely, summer months (June to August) see smaller swells (1.1-1.4m) dominated by wind swell, which is less consistent, but the likelihood of good offshore winds improves (30-38%). For advanced surfers prioritizing wave quality, autumn and winter (especially October to March) are optimal despite the challenging winds, while beginners or those preferring lighter conditions might find late spring or early summer more manageable, albeit with less swell energy. September and April serve as transitional months, balancing decent swell size (1.6-2.1m) with marginally better wind odds. Overall, if you’re chasing size and consistency, target November to February; if you prefer smaller waves and fewer crowds, consider May to September, accepting the trade-off of reduced swell power.