Castles
Hourly
Confidence
Compare
⏱️s.
⚡️kJ
Sunday 30
Monday 01
Tuesday 02
Wednesday 03
Thursday 04
Timezone:
Asia/Tokyo
Wind: ⭐ UNIFIED
(20251130 02z)
Waves: ⭐ UNIFIED
(20251130 02z)
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Castles surf forecast characteristics

Swell window
E - S
(Best from SE)
Swell size
2ft - 6ft
Swell breaks over
Live Coral
Wave types
Point
Wave directions
Left
Wind window
N - N
(Offshore from N)
Works at
Mid, High
Skill Level
Expert

Castles surf forecast guide

Castles is a surf spot that’s a bit of a trek from the cliffs parking area, which keeps it less crowded compared to other nearby spots like Suicide Cliffs. It’s located on an exposed point of the island, making it pretty consistent. The walk might be a hassle for some, but it means you can enjoy a more peaceful surf session away from the crowds. If you’re up for the hike, Castles offers a rewarding experience.

The waves here are mostly lefts, breaking over live coral, and the optimal swell direction is from the southeast. It works well on swells coming from the east and south, handling sizes of 2 to 10 feet (about 0.6 to 3 meters). For the best results, aim for mid to high tide, and you'll find the waves more favorable when the wind is coming from the north. This spot is more suited for expert surfers, so if you're looking for a challenge, Castles might be your place.

Since it’s less crowded, you can find more space to ride those longer sections of the waves. Just remember that a solid hike is part of the deal, but it can pay off in a solid surf session with fewer people around. Keep an eye on the conditions before heading out, and enjoy the surf at Castles!

Surf schools and rentals

Surf reports and surf forecasts nearby Castles

Bowls
Okinawa, Japan
Reef break
Sun 30
Mon 1
Tue 2
Wed 3
Thu 4
Aja
Okinawa, Japan
Reef break
Sun 30
Mon 1
Tue 2
Wed 3
Thu 4
Kudaka
Okinawa, Japan
Reef break
Sun 30
Mon 1
Tue 2
Wed 3
Thu 4
Suicide Cliffs
Okinawa, Japan
Reef break
Sun 30
Mon 1
Tue 2
Wed 3
Thu 4
Castles
Okinawa, Japan
Point break
Sun 30
Mon 1
Tue 2
Wed 3
Thu 4
Confidence

Confidence tells you how much the weather models agree on the forecast.

  • High confidence: Models agree closely; forecast is reliable.
  • Medium confidence: Some disagreement; conditions may shift slightly.
  • Low confidence: Models diverge; treat forecast with caution.

We calculate the wind confidence by comparing wind speed, gust and direction from multiple models (like GFS, ECMWF, Arome, and Harmonie) and seeing how closely they match. For wave certainty we compare height, period and direction, also on multiple models. They are weighted, meaning that some models count more than others, depending on how good they are for a certain spot.

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Readme

Welcome! If you’re new to surf forecasting, check out this quick guide.

Forecast Table

The forecast table (the section on the page with all the numbers) is designed to pack as much information in the screen as possible. Although intimidating at first, it will help you make informed decisions about the waves faster, trust me :D. The table consists of roughly four sections, time and predictions, wind, waves, and tides:

🔮 Time and predictions section

Here we show the forecast thour and the overall surf quality prediction. This is determined based on the wave, wind and tide quality prediction. These individual predictions can be found on the forecast map.

💨 Wind section

The first row on the table (with the 💨 icon) shows wind speed, direction and gust. The more the wind speed the more aggressive the color (from blue, green, orange to red).

🌊 Wave section

The waves section consists of three rows, one for wave height and direction, one for period and one for wave energy. Our algorithm choices the "dominant wave". This is normally the first swell partition, but with heavy local storms it displays the wind waves. If that's the case, we display the numbers in italic and in gray.

🌒 Tide section

The tide section consists of a row with the actual heights per hour (measured at the half hour) and a table that displays the flow of the tide and the extremes (lows and highs).

Forecast map

The forecast map consists of arrows. These arrows represent all wave partitions (swell partitions and wind wave partition) and the wind. This allows you to see things like: a secondary swell or wind waves messes up the surf, or the wind is just a tick offshore so very surfable. Click a metric label in the bottom left to bring that arrow to the front — handy when arrows overlap.

Forecast Cheat Sheet

Short on time? Focus on wave energy. It’s the best single metric to gauge how big and powerful the waves will be.

Click any table cell to jump to that forecast hour. The map will update with forecast arrows, so you can see if wind and swell direction are lining up.

Use the table sidebar to switch units for height and speed.

Log your surf sessions to compare forecasts with real sessions and sharpen future predictions.

Models and Updates

Surfnerd blends multiple global and local wind and swell models using advanced interpolation and spatial techniques to create an "ensemble" forecast. Forecasts are refreshed hourly.

Surf Predictions

Our AI-driven algorithm scores surf quality, shown by green, orange, and gray dots. Each forecast hour is rated for wind, swell, and tide quality, then combined into an overall score. Here’s the scale:

Perfect
Good
Average
Bad or No Data

Session logs also feed the algorithm — the more you log, the smarter your forecasts get.

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