Guilderton Rivermouth 83.8
#594 of 5756 surf spots in the world · 🇦🇺 Australia · Western Australia · near Gingin
Works almost every day, no off season.
Best time to surf Guilderton Rivermouth
The best time to surf Guilderton Rivermouth is April, May, June. The season runs Jan to Jun. In May the water sits around 22°C, so pack a 2 mm shorty, and the typical wave is 2.0 m. The nearest airport is PER (79 km) and the nearest town is Gingin (38 km).
| Month | Surfable | Clean | Size | Water | Suit |
|---|---|---|---|---|---|
| Jan | 100% | 44% | 1.8 m | 22°C | vest |
| Feb | 100% | 50% | 1.7 m | 22°C | vest |
| Mar | 100% | 61% | 1.6 m | 22°C | vest |
| Apr | 100% | 75% | 1.9 m | 22°C | 2mm |
| May | 95% | 81% | 2.0 m | 22°C | 2mm |
| Jun | 94% | 70% | 2.2 m | 21°C | 2mm |
| Jul | 91% | 36% | 2.5 m | 19°C | 2mm |
| Aug | 91% | 53% | 2.4 m | 19°C | 3/2 |
| Sep | 97% | 56% | 2.2 m | 18°C | 3/2 |
| Oct | 99% | 41% | 2.1 m | 19°C | 2mm |
| Nov | 100% | 46% | 1.8 m | 20°C | 2mm |
| Dec | 100% | 31% | 1.8 m | 22°C | 2mm |
What is under Guilderton Rivermouth
Eight kilometres out along its swell window the sea floor sits over 37 m. Alongside the bank the survey finds a channel, 54 m against 37 m, deep enough to bend swell onto one peak instead of spreading it along the beach.
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 83.8
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 235° with 44% open water around it. Friendly morning wind 62% of days. Mean peak period 12.9 s. Days over 3 m: 11%. On its best tenth of days it reaches 3.1 m, with a peak period of 14 s. Mellow days (0.4 to 1.2 m): 5%. Months that work: 12 of 12. Coordinates -31.353, 115.499 (OpenStreetMap).
What it costs to be here
Estimate: World Bank PPP price level for Australia (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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