Surf forecastStatisticsHistorical report

San Blas seasonal overview

Best Surf Season (November - February & July - August)

The heart of the surf calendar at San Blas delivers a classic combo of consistent, long-period SSW swell and reliable offshore winds from the north quadrant. In winter, the North Pacific storm track fires up, sending powerful groundswells marching toward the Central American coast with average wave periods between 12 and 13 seconds and heights in the fun-to-good 1m range. Simultaneously, the strengthening of the North American high-pressure system funnels steady offshore breezes from N/NE, keeping the wave faces clean and groomed. During July and August, a secondary peak emerges as the tropical trade winds relax, allowing a higher percentage of light offshore winds while the swell from the Southern Hemisphere remains strong, pushing average heights above 1.3m and periods above 13s. These months offer the best mix of power and shape for a rippable, walled-up wave.

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

Transitional months bring a trade-off: the swell builds in height and period, often reaching peak averages above 1.2m and periods of 14s, but the offshore wind reliability begins to fade. March and April see the offshore wind percentage drop to 47% and 40% respectively, as the region starts to feel the influence of the Intertropical Convergence Zone (ITCZ), which can introduce more onshore components from the south and southwest. September and October are similar: the swell remains solid, with SSW directions dominating over 73% of the time, but the window of clean offshore wind narrows to around 51-54%. Morning glassy conditions are common, but afternoon sea breezes can quickly mess things up. Still, when the right combination emerges – a good S-SSW groundswell coupled with a north wind – the waves are long, powerful, and well-shaped.

Low Surf Season (May - June)

The low point of the year at San Blas is less about lack of swell and more about wind consistency. May and June still produce solid SSW groundswell with average heights rising to 1.4m and periods holding at 14s, but the percentage of ideal offshore wind plummets to 42% and 53% respectively. The ITCZ sits overhead, bringing frequent light onshore winds from the south and southwest, which degrade wave quality and create bumpy, less organized surf. Additionally, the increased tropical moisture can lead to overcast skies and occasional thunderstorms. While the swell is far from flat, the onshore bias means you'll often be scratching for clean peaks. Look for early mornings or days when a weak cold front pushes north winds back down – those are the jewels in an otherwise fickle period.

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Conditions at San Blas in May

May: Solid Swell, Tougher Conditions

May holds strong with an average swell height of 1.4m and period of 14.2s, matching April for size and power. The swell remains overwhelmingly SSW (87.5%), with minor S (7.9%) and SW (4.1%) contributions. This is true groundswell territory – expect heavy, long-period lines that jack up fast over the reef. The catch? Ideal wind drops to 42% as the ITCZ moves overhead. Offshore flow from N, NNE, NE, and ENE totals only about 23.5% of the time, while light onshore winds from the southern quadrant (S, SSW, SW, W) combine for over 33%. The result is a month where you'll need to hunt for early morning windows or days when a passing front pulls the wind north. Despite the challenging wind, the sheer volume of swell means there are still plenty of rideable waves – just expect bumpier faces.

Average Spot conditions at San Blas in May

Swell history for May

0 - 0.5
0.5 - 1
1 - 1.5
1.5 - 2.0
2.0 - 2.5
> 2.5 m

Wind history for May

0 - 10
10 - 20
20 - 30
30 - 40
40 - 50
> 50 km/h

Swell quality

Analyze the groundswell consistency at San Blas during May. Based on historical data, there is a % probability of groundswell occurring this month. The chart below provides a detailed breakdown of the average wave height distribution, offering deep insights into the swell quality and surf potential you can expect at San Blas for your next trip in May.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at San Blas for May. Our analysis shows that favorable offshore or side-shore winds coincide with surfable swell approximately % of the time. The accompanying graph illustrates the average size distribution of waves during these optimal wind windows at San Blas.

Swell with good wind

Swell with good wind by size