How it works

Every morning a small script fetches the wind and rain forecast for each island from MET Norway. Then it works out, for every beach, what that wind does to the water there.

Sea state

Each beach has a direction it faces (the way you look when you stand at the water) and a shelter factor for reefs, breakwaters and bays. Wind blowing from the sea onto the beach builds waves. Wind blowing from the land flattens them. We take the part of the wind that blows onshore, add a little for wind along the beach, reduce it for shelter, and call the result:

Calm: Flat or rippled water. Good for swimming, children and snorkelling.
Light chop: Small waves. Fine for swimming; snorkelling is murkier near the shore.
Choppy: Waves and wind on the beach. For confident swimmers; poor for snorkelling.
Rough: Waves and current. Not a swimming day here.

Morning and afternoon are rated separately, because the trade wind usually picks up after noon.

Crowds

Each beach starts at its ordinary weekday level (quiet, normal or busy). Beaches that are local favourites get busier on Sundays and public holidays. On Aruba, we add cruise passengers from the port's published schedule: on days with thousands of guests ashore, the beaches closest to town and the hotels fill up. For Bonaire and Curaçao we have no cruise schedule we may use, and the pages say so.

What we cannot see

Swell from far away. After storms in the Atlantic, waves can reach even the calm side.
Currents, jellyfish, sargassum seaweed and water quality.
Events, parties and closures.

So: it is a planning aid, not a safety service. Follow local warnings, flags and lifeguards.

Facts about beaches that we have not yet checked on the island carry a being verified label.

Sources

Wind, rain and temperature: MET Norway Locationforecast, CC BY 4.0.
Cruise ships in Aruba: Aruba Ports Authority (provisional schedule). Guest numbers are ship capacity.

Made by a sailor who lives aboard in Aruba. Not affiliated with any tourism board, port or beach club.