READ THE BREAKBEFORE IT BREAKS
Offshore swell changes shape between the buoy and the sandbank. The forecast accounts for what happens in between.
FROM BASIN TO BEACH
Energy travels, bends, and dissipates before it reaches the lineup.
GENERATION
Track basin-scale wind forcing and offshore energy formation.
PROPAGATION
Model travel speed, decay, and direction shifts across the shelf.
TRANSFORMATION
Apply depth and orientation effects that reshape wave quality.
BREAK-LEVEL OUTPUT
Present likely session windows with confidence and limiting factors.
WHAT YOU ACTUALLY GET
Windows, limiting factors, and how sure we are. When the forecast is shaky, you see why.
OPTIMAL WINDOW
Time
07:00 – 09:00
Conditions
High tide, offshore, 11s period
Swell
1.1m @ 11s
Wind
4kt S (offshore)
Tide
High at 08:15
Direction
SW 210°
FREE SIGNAL. PRO DEPTH.
The surf call is free. The reasoning behind it is Pro.
FREE
The call
Today's window, the five-day outlook, data freshness, safety context. Enough to decide whether to go.
PRO
The reasoning
For surfers who want to know why the call is what it is.
- Full wind and swell analysis
- Break-level intelligence
- Session match and journal depth
- Spot optimizer and forecast reliability
SOURCE TO SHORE
Offshore buoy readings don't tell you what reaches the beach. We model energy loss, refraction over bathymetry, and nearshore shoaling so the number on screen is the wave that arrives.
GROUP VELOCITY ETAs
Arrival windows from wave period physics, not rule of thumb.
BUOY NETWORK TRACKING
Energy picked up offshore and propagated forward to your coastline.
SHALLOW-BANK ATTENUATION
Energy lost crossing Dogger Bank and other shallows, accounted for with bathymetry.
NARROW ARRIVAL WINDOWS
Where period, direction, tide, and wind align — and why.
Deep Water Group Velocity
Cg = gT / (4π) ≈ 0.78 × T (m/s)T is wave period in seconds. A 15-second groundswell travels at ~11.7 m/s.
DEPTH OVER THE BANKS
On the southern North Sea, sandbanks sit offshore in shallow water. At low water they absorb the swell before it reaches the beach. The forecast accounts for tide stage at each break.
Outer banks absorb the swell. Flat at the beach.
Banks still bleeding off energy. Marginal.
Enough water over the banks. Swell reaches the beach.
FORECAST VS WHAT YOU PADDLE INTO
Standard forecast
"1.2m @ 10s from WNW" — reads surfable.
Tide-adjusted
Flat at the beach until 14:30. Window opens through the high, then closes with the drop.
Regional tide dependency
Belgium (Oostende, De Panne, Knokke)
Flat at low water
Zeeland (NL)
Rideable, off-peak
North Holland (NL)
Larger swells push through
DIRECTION FIRST
Wind direction relative to the beach decides whether the face holds or breaks up. Speed determines how forgiving that direction is.
Land to sea. Holds the face open at moderate speed.
Along the beach. Rideable, but shape depends on shielding.
Sea to land. Chops the face and stacks swell on swell.
SPEED PENALTY
Even offshore goes off above a certain speed. Penalties stack with the direction score.
NORTH SEA BASIN
Tide-adjusted forecast windows, calibrated against buoy data along the southern North Sea coast.
BE / BELGIUM
BLANKENBERGE
Flemish Banks. Tide-dependent.
NL / NETHERLANDS
SCHEVENINGEN
Open North Sea exposure.
DK / DENMARK
KLITMØLLER
Wind swell, exposed coast.
THE FORECAST IS LIVE
Belgium and the Netherlands, calibrated at break level. No login, no waitlist — get it on iPhone or open it in your browser.