Dadonghai 51.8
#3905 of 5756 surf spots in the world · 🇨🇳 People's Republic of China · Hainan · near Sanya
Very consistent, wind is the enemy here, no off season.
Best time to surf Dadonghai
The best time to surf Dadonghai is October, November, December. It rarely works. In December the water sits around 25°C, so pack a rash vest or 2 mm, and the typical wave is 1.6 m. The nearest airport is SYX (15 km) and the nearest town is Sanya (4 km).
| Month | Surfable | Clean | Size | Water | Suit |
|---|---|---|---|---|---|
| Jan | 100% | 1% | 1.2 m | 23°C | vest |
| Feb | 94% | 0% | 1.0 m | 24°C | vest |
| Mar | 89% | 0% | 0.9 m | 25°C | vest |
| Apr | 85% | 1% | 0.8 m | 27°C | boardies |
| May | 72% | 0% | 0.7 m | 29°C | boardies |
| Jun | 87% | 0% | 0.8 m | 30°C | boardies |
| Jul | 75% | 0% | 0.8 m | 29°C | boardies |
| Aug | 73% | 0% | 0.8 m | 29°C | boardies |
| Sep | 57% | 2% | 0.7 m | 29°C | boardies |
| Oct | 91% | 3% | 1.4 m | 28°C | boardies |
| Nov | 97% | 3% | 1.3 m | 26°C | boardies |
| Dec | 100% | 9% | 1.6 m | 25°C | vest |
What is under Dadonghai
Eight kilometres out along its swell window the sea floor sits over 34 m.
Measured, not estimated: NOAA ETOPO 2022 global relief at 15 arc-seconds, about 460 m per cell, sampled along this spot’s own swell window. At that scale the survey sees passes and channels; it cannot see a reef ledge, so nothing here is said about how the wave breaks.
Why 51.8
Seven parts, each normalised 0 to 1 and multiplied by its weight; the sum is scaled so the best spot in the world scores 100. Wave quality and what the spot does on its best days carry more than half of it, which is what separates this from a ranking of where the water is warm.
The detail
Faces 161° with 42% open water around it. Friendly morning wind 59% of days. Mean peak period 7.4 s. Days over 3 m: 0%. On its best tenth of days it reaches 1.8 m, with a peak period of 9 s. Mellow days (0.4 to 1.2 m): 66%. Months that work: 12 of 12. Coordinates 18.221, 109.518 (OpenStreetMap).
What it costs to be here
Airport and town on the doorstep, so the local estimate is 23% above the country average. Estimate: World Bank PPP price level for People's Republic of China (2025, United States = 1.00) applied to a fixed surfer basket, then adjusted for how remote the spot is. Your own number moves with the season and how you live.
Sumba has eight spots in this ranking, the best of them inside the world top 50. A cabin is €11,500. The land it sits on is separate, from €6,500 (€9,950 oceanfront), on an 80-year lease that extends at the end. Water, septic and electricity are another €6,500, and furniture is on top, so a finished cabin lands around €28,000 plus the land, payable in instalments.
Eco Beach City is run by the same people as SurfRanking, so treat this as our own advert, not a recommendation. It is an off-plan property in Indonesia: take your own legal and financial advice before paying anything.
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