Today — sit it out — wave, wind and visibility.
Sources & confidence
Compiled by the spearo sea-state engine · How it works →
The verdict comes from seven water factors and hard safety gates — not ten tabs. Go or stay.
Our own model
Our own forecast engine — not a third-party widget. It weighs these water factors into one go-or-stay verdict for this coast; the 0–10 dial is that verdict, read out as a number.
Safety gates
It all folds into a single 0–10 score and one verdict: go or stay.
A forecast, not a guarantee — the sea has the last word.
Where to get in, where to hunt
Wind, wave and the swell windows — when to go and the best hours.
The day is picked above, in the hero. Here are that day's windows, the hour-by-hour map and the trends. Tap a window to break down the conditions.
Leave your email — and the moment a window opens at Similan Islands, we'll send the go / no-go verdict. Email is all we need.
What's missing? Tell us what you'd like to see — new spots, species, data or features. We read everything.
Visibility and what drives it — post-storm clearing, river plume, temperature and the thermocline.
spearo.app folds wind, wave, swell period, visibility, tides, water temperature and risk into a single verdict — go to the spot or not. It computes 7 days ahead from open marine models (Open-Meteo, IPMA), with no sign-up and no accounts. Built for solo spearfishing off the rocks, where any mistake costs dearly.
Now live: 3016 spots across 406 stretches of coast — mainland Portugal, Madeira and the Azores.
See all spotsRelief and bottom type, tides, and the depths of each spot.
The models set the window. Whether you go in is read only at the water: count the sets, watch the surge on the entry. If in doubt, you don't get in.
Scouted entries, coloured by today. The colour is the sea state at the spot, not a guarantee: the wash and a slippery entry you judge on site.
Open the seafloor mapListed dive site, typical depth 10 m, max 40 m, near shore. No hunting — Mu Ko Similan National Park; freediving/visibility point. Coords from a dive-site database, approx.
Google MapsListed dive site, typical depth 20 m, max 37 m, near shore. No hunting — Mu Ko Similan National Park; freediving/visibility point. Coords from a dive-site database, approx.
Google MapsListed dive site, typical depth 20 m, max 45 m, near shore. No hunting — Mu Ko Similan National Park; freediving/visibility point. Coords from a dive-site database, approx.
Google MapsListed dive site, typical depth 20 m, max 36 m, near shore. No hunting — Mu Ko Similan National Park; freediving/visibility point. Coords from a dive-site database, approx.
Google MapsListed dive site, typical depth 25 m, max 70 m, near shore. No hunting — Mu Ko Similan National Park; freediving/visibility point. Coords from a dive-site database, approx.
Google MapsListed dive site, typical depth 18 m, max 40 m, boat access. No hunting — Mu Ko Similan National Park; freediving/visibility point. Coords from a dive-site database, approx.
Google MapsSOLO is the biggest risk: underwater you can black out from lack of oxygen silently and fatally, with no one around. Solo is never truly «safe». Below are the best weather windows; carry a buoy, tell someone your plan and exit time, and any doubt — don't go.
Cameras, map and reference — to hand as you come up.
Spearfishing has no national ban in Thailand, but it is prohibited in every national park — most offshore islands and reefs — where taking animals and bringing in hunting gear or weapons is banned (National Parks Act B.E. 2562, s.19). Check provincial rules; breath-hold only.
Similan Islands has rock entry points such as Elephant Head, East of Eden and Anita's Reef. Granite archipelago 60 km off Khao Lak, all inside Mu Ko Similan National Park: no take of any kind and no spearguns on board. Below you'll find each spot (access, shelter and hazards) and today's forecast.
November–April (north-east monsoon, calm sea); May–October the south-west monsoon closes the coast and most marine parks.
28–30 °C all year — a rashguard or 1.5–3 mm.
Granite boulders and coral reefs, currents around the offshore islands; most islands are national parks where hunting is banned.
Similan Islands: Spearfishing has no national ban in Thailand, but it is prohibited in every national park — most offshore islands and reefs — where taking animals and bringing in hunting gear or weapons is banned (National Parks Act B.E. 2562, s.19). Check provincial rules; breath-hold only.
transparency ~22 m · satellite, yesterdaysatellite estimate · may differ right at the shore
