Racetrack - Sumba
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Hourly
Timezone: Asia/Makassar
โฑ๏ธs.
โšก๏ธkJ
Tuesday 21
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Tap a forecast cell to explore conditions on the map.

Racetrack - Sumba surf guide

Racetrack is a surf spot located in Sumba that offers a bit of a challenge for those who are looking to test their skills. The waves here can get pretty action-packed, making it a spot that suits expert surfers the best. While itโ€™s got its moments, itโ€™s not always consistent, so you might find yourself waiting for the right conditions.

The surf here generally works best at mid tide, providing a steep drop into a barrel section that can really pump out some fast walls. The optimal swell direction is from the Southwest, but you can also catch decent waves when the swell comes from the West. This place can handle swell sizes starting from around 2ft (0.6m), with left-breaking reef waves that can deliver some fun rides. If you're planning to surf here, the best wind direction is from the Northeast, so check the forecasts!

For those heading to Racetrack, remember itโ€™s all about the right conditions. Make sure youโ€™re ready for an expert level challenge, as the waves can be demanding. Overall, itโ€™s a spot that can offer good days if the swell is right and the tides align.

Surf reports and surf forecasts nearby Racetrack - Sumba

Savu Right
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
Savu Left
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
Raijua
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
The Office
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
Five-O
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
Racetrack - Sumba
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
Miller's Rights
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
Wainukaka
Unknown Region, Unknown Country
Rivermouth break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
Pulau Dana
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
Mangkudu Lefts
Unknown Region, Unknown Country
Reef break
Tue 21
Wed 22
Thu 23
Fri 24
Sat 25
Sun 26
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat 1
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Readme

Welcome! If youโ€™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:

๐Ÿ”ฎ 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.

๐Ÿ’จ Wind section

The first row on the table (with the ๐Ÿ’จ icon) shows wind speed, direction and gust. The more the wind speed the more aggressive the color (from blue, green, orange to red).

๐ŸŒŠ 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.

๐ŸŒ’ 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 โ€” handy when arrows overlap.

Forecast Cheat Sheet

Short on time? Focus on wave energy. Itโ€™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. Hereโ€™s the scale:

Perfect
Good
Average
Bad or No Data

Session logs also feed the algorithm โ€” the more you log, the smarter your forecasts get.

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

Wind certainty

Wind certainty tells you how much the weather models agree on the forecast.

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

We calculate this by comparing wind speed, gust and direction from multiple models (like GFS, ECMWF, Arome, and Harmonie) and seeing how closely they match. 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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