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Surf forecast for Asu

Tide
⏱️s.
⚡️kJ
Timezone:
Asia/Jakarta
Forecast updated:
22/06, 19:00
Wind: SN UNITY Atmos
(20260621 12z)
Waves: SN UNITY WAVE
(20260621 12z)
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Timeline

Asu Surf Forecast Guide

Asu is a small island located just off the coast of Nias, Indonesia, and it's known for its remote and rugged beauty. The island is about 65 km (43 mi) and a 5-hour boat ride from the southern town of Teluk Dalam. While it's a bit of a trek to get to, it’s worth it for those looking for a more off-the-beaten-path surf experience. The area offers long, sweeping left-hand waves that break over a shallow reef, providing an exciting challenge for surfers who are up for it.

The best conditions for surfing at Asu come from a southwest swell, but it can also handle swells from the south and west. Waves can reach sizes up to 3 ft (about 0.9 m) and break over dead coral, which makes for a unique ride. The waves are primarily lefts, and speed is key when navigating through some of the pinching sections, especially as the wave can get heavy at size. It's crucial to be cautious of the impressively long and shallow reef. The waves can work at any tide—low, mid, or high—which is a bonus. This spot is recommended for expert surfers due to the challenging conditions, including the notorious “Nuclear Zone” reef at the shallow end.

Getting in and out of the water can be tricky due to the coral scramble around the land camps, so make sure to bring booties to protect your feet. The east wind is preferable for the surfing conditions, which can enhance your experience on the waves. Overall, Asu offers a unique surf experience that suits those looking for adventure and are equipped to handle the intensity of the waves.

Surf spots near Asu

Afulu
North Sumatra, Indonesia
Reef break
Mon 22
Tue 23
Wed 24
Thu 25
Fri 26
Asu
North Sumatra, Indonesia
Reef break
Mon 22
Tue 23
Wed 24
Thu 25
Fri 26
Bawa
North Sumatra, Indonesia
Reef break
Mon 22
Tue 23
Wed 24
Thu 25
Fri 26
Shark Hole
North Sumatra, Indonesia
Reef break
Mon 22
Tue 23
Wed 24
Thu 25
Fri 26
Lagundri Bay - Indicators
North Sumatra, Indonesia
Reef break
Mon 22
Tue 23
Wed 24
Thu 25
Fri 26

Frequently asked questions

What are good surfing conditions for Asu?

Asu is usually best with swell from south to west (S-W), ideally southwest (SW) around 0.9 m / 3 ft to 5.5 m / 18 ft, east (E) offshore wind, and any tide.

Where is the surf spot Asu?

Asu is a surf spot in Bawosaloo, North Sumatra, Indonesia.

What is the surf break like at Asu?

Asu is a left reef break over dead coral. Expect a moderate crowd.

What surfing skill level is Asu suitable for?

Asu can suit expert surfers.

Is Asu beginner friendly for surfing?

Asu is better suited to expert surfers.

How consistent is the surf at Asu?

Asu is one of the more consistent surf spots in North Sumatra, Indonesia.

What surf spots are near Asu?

Other nearby surf spots are Bawa, Afulu, Shark Hole, and Lagundri Bay - Indicators.

What swell direction works for surfing at Asu?

Asu can work with swell from south to west (S-W); southwest (SW) is usually best.

What swell size works for surfing at Asu?

Asu usually works with swell around 0.9 m / 3 ft to 5.5 m / 18 ft.

What wind direction is best for surfing at Asu?

East (E) offshore wind is usually best at Asu.

What wind direction is offshore for surfing at Asu?

East (E) is offshore at Asu.

What tide works best for surfing at Asu?

Asu can work on all tides. A rising tide is usually better here.

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:

đź”® 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.

đź’¨ Wind section

The first row on the table (with the đź’¨ 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 chooses the "dominant wave" using spot-adjusted surf energy (depth + directional fit). This is usually the first swell partition, but during local storms it can switch to wind waves. If that happens, values are shown in gray and italic.

🌒 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.

With Surfnerd, no more "you should have been here yesterday"

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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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