Dum Dums
Hourly
Confidence
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Tap a forecast cell to explore conditions on the map.
Timezone: Australia/Sydney
Wind: GFS (20251102 18z)
Waves: GFS WAVE (20251102 18z)

Dum Dums surf guide

Dum Dums is a surf spot located on Crampton Island, known for its shallow reef that can deliver some quick and hollow waves. The spot works best when the combination of sandbanks, a small Northeast to Southeast swell, and the right tide come together. It’s a good spot to hit if you’re looking for something not overly crowded, with a scenic bush backdrop that adds to the vibe.

The surf here tends to favor Southeast swell directions, though it can also handle some Northeast swells. It works well with wave sizes around 2 feet (0.6 meters) and breaks over an uneven reef and sand. Most of the waves are right-handers, perfect for those who are more experienced. The ideal conditions come with a Northwest wind and during mid to high tide, making it a much better session if you know what you’re doing.

Dum Dums is generally not for beginners, so make sure you have your skills dialed in before you head out. The setup can be tricky, and the conditions might not always be perfect, but for expert surfers looking for a challenge, it’s definitely a spot worth checking out.

Surf reports and surf forecasts nearby Dum Dums

Rennies Beach
New South Wales, Australia
Beach break
Mon 3
Tue 4
Wed 5
Thu 6
Fri 7
Sat 8
Sun 9
Mon 10
Tue 11
Wed 12
Thu 13
Fri 14
Dolphin Point
New South Wales, Australia
Reef break
Mon 3
Tue 4
Wed 5
Thu 6
Fri 7
Sat 8
Sun 9
Mon 10
Tue 11
Wed 12
Thu 13
Fri 14
Dum Dums
New South Wales, Australia
Reef break
Mon 3
Tue 4
Wed 5
Thu 6
Fri 7
Sat 8
Sun 9
Mon 10
Tue 11
Wed 12
Thu 13
Fri 14
Bawley Point
New South Wales, Australia
Point break
Mon 3
Tue 4
Wed 5
Thu 6
Fri 7
Sat 8
Sun 9
Mon 10
Tue 11
Wed 12
Thu 13
Fri 14
Guillotines
New South Wales, Australia
Reef break
Mon 3
Tue 4
Wed 5
Thu 6
Fri 7
Sat 8
Sun 9
Mon 10
Tue 11
Wed 12
Thu 13
Fri 14

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.

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

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

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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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