spearo sea-state engine: consensus of up to 6 models + satellite clarity (ZSD) + buoy-bias checks
Freshness
Re-read every hour, per coast
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.
How we score the water
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.
01
Swell & wave memory
Height, period and direction of the swell, plus the wake of recent storms — an old storm still stirs the water, and the engine remembers.
02
Wind & gusts
Speed and gusts, hour by hour — wind speed and an onshore push chop the surface and cut visibility.
03
Tide phase
Timing and range of the tide, calibrated per coast — big spring tides pull the verdict toward caution.
04
Water temperature
Sea-surface temperature — sharply cold water vetoes a green verdict.
05
Currents & outflow
Direction and drift of the current — it pushes you, and it drags turbid coastal water across where you dive.
06
Rain runoff & air clarity
Rain muddies the water inshore through land runoff, while fog and haze cut visibility at the surface.
07
Coast shape & exposure
How the coast faces the swell — a sheltered cove keeps the water clean; an exposed, head-on point takes a penalty.
Safety gates
Thunderstorm forecast — an instant red, no exceptions.
An official warning (MeteoAlarm / IPMA) — yellow, or red for the higher ranks.
Missing input data — a would-be green is capped to yellow rather than overstated.
Strong disagreement between forecast models — a green day is pulled back to yellow.
Night hours — where night spearfishing is banned by law the window is forced red; where it is legal (Australia outside NSW, New Zealand, South Africa) it is capped at yellow, never green.
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
Entry points with coordinates
Seabed relief — promising ground
This verdict — in your pocket. Open the app for the week's window.
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0 m
Surface
Wind, wave and the swell windows — when to go and the best hours.
spearo.app
no dataupdated 20:55
Getxo (Bilbao) — solo, off the rocks
DON'T GO
don't go · wave 2.3 m (occasionally up to ~4.6 m)
wave 2.3 mwind 10 km/hsurge pounding the rocksvisibility ~1 m
today, best window 06:00–09:00
fish · Visibility 1 m · Water 18.3°C
confidence low · verdict for the selected day
Whole week — tap a day. is driving swell right now.
›
Solo risk: carry a float · tell someone your plan and exit time · doubt = don't go. A model-based planner; the call is made on site.
Selected day
Windows, hours and the day's trends.
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.
Sunday · today2026-10-25
08:38–19:13 · full moon
▲ 04:00▼ 10:00▲ 16:00▼ 22:00mid-range tides · 3.7 m
Hours (06→20)
06
09
12
15
18
Day's trends
Tide-2.10 m
Wave2.48 m
Wind5 km/h
Water18 °C
fish activity: moon overhead 00:50 · high · moonset 07:46 · moderate · moon underfoot 13:10 · high · moonrise 18:32 · moderate
Conditions window06:00–09:00
don't go fish
Hs 2.32 m · roughperiod 9.2 swind 10→16surge 49.3viz 1 m
What's missing? Tell us what you'd like to see — new spots, species, data or features. We read everything.
Your best window — with you. Forecast in your pocket.
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−10 m
The water column
Visibility and what drives it — post-storm clearing, river plume, temperature and the thermocline.
What it is
A marine instrument, go / no-go for solo hunting.
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.
SOLO 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.
One morning glance — and you know.
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≈
Surfacing
Cameras, map and reference — to hand as you come up.
✓Spearfishing licence mandatory; the AUTONOMOUS COMMUNITY issues it (not the State) and it is valid in the exterior waters of the whole coast. Free-diving only — scuba is banned (, art. 3).
✓Spearfishing catch may not be sold or traded — it is non-commercial fishing ().
✓Night prohibited: spearfishing only in daylight (sunset to sunrise not allowed) — , art. 16.d.
✓Marker buoy MANDATORY: mark your position with a clearly visible buoy and stay within 25 m of it — , art. 15.
✓Never keep the speargun loaded out of the water — , art. 16.a.
✓Keep at least 300 m from professional fishing vessels that are working — , art. 12.b.
✓The state act (, art. 16) bans, for spearfishing: a loaded gun out of the water; explosive/electric points and lamps (hand torches excepted); underwater scooters; night — from sunset to sunrise. Plus art. 12 b), d), e): 300 m from professional fishing vessels, light as an attractant, poisons/explosives. A ban in a PARTICULAR reserve, port or beach comes from that place's OWN instrument (the reserve's order, the autonomous community's rules, the port authority) — see the no-take zones on the map and your community's rules.
✓Min. sizes by ( + + EU 2019/1241): sea bass 42 cm (rec.) / 36 cm / 25 cm Mediterranean / 22 cm Canaries; gilthead bream 20 cm and white seabream 23 cm in the Mediterranean (EU 2019/1241); grouper 45 cm. See your zone's species card.
✓Only species in Annex I of may be taken; keeping, landing or transporting undersized specimens is prohibited.
✓The licence needs a medical fitness certificate for free-diving and civil-liability insurance (or a federative licence, which includes it). Mandatory in the Basque Country/Murcia/Asturias/Galicia; the federative licence covers it in Galicia/Balearics/Cantabria; the Canaries and Andalusia do NOT require it for the individual licence (a responsible health declaration). Minimum age generally 16 (14 in Andalusia).
Safety protocol
Sets: watch the wave trains ≥15 min before entering; Hmax ≈ 2×Hs, the wash can run 50 m past the foam line. A lull >10 min with period >12 s = a big set «overdue», do NOT enter; enter right after a full set passes and re-check at minute 30.
Exit FIRST: find your exit AND a backup before entering. On a rocky/boulder shore a 0.5 m rise in swell can make the exit impossible — getting pinned/unable to climb out is the main killer.
Headland rip: prominent points often have a permanent topographic rip regardless of the model — locate it, enter/exit on the windward side, never swim against it.
Cold: wetsuit per the SST chip; the first shiver = a metabolic surge and a drop in breath-hold → get out at the first steady shiver. Cap the session at 45–60 min below 15 °C.
Solo discipline: buoy up; tell someone the spot and exit time; conservative breath-hold (never push it in cold/murky/surfy water); visibility <3 m — don't enter.
Afternoon wind: on many coasts the wind builds from midday — plan to be out of the water by midday; the chop builds — get out.
UV 11:00–15:00 (UVI ≥6): sunscreen and cover up on the surface interval.
Solo is a fundamental risk (hypoxic blackout with no buddy). Any doubt = No-go.
FAQ — spearfishing in Getxo (Bilbao)
Where can I spearfish in Getxo (Bilbao)?
Getxo (Bilbao) has rock entry points such as Punta Galea, Arrigunaga (Tunelboca) and Gorrondatxe – Azkorri. Getxo guards the mouth of Bilbao's estuary and looks north-west. Below you'll find each spot (access, shelter and hazards) and today's forecast.
When is the best season in Getxo (Bilbao)?
Summer and early autumn are the windows — in winter the Bay of Biscay swell shuts the coast down. Tides are large (4 m+) and set up current, so pick a small-sea day with the tide in your favour.
How cold is the water in Getxo (Bilbao)?
~14–22 °C: cool, but it warms up in the summer window. A 5 mm suit at peak summer, 7 mm with a hood the rest of the year.
Is Getxo (Bilbao) good for a beginner?
Demanding: strong Biscay swell, big tides and exposed rock entries. It's for those who can already read the sea and pick the window well — not a coast to start on.
Do I need a licence in Getxo (Bilbao)?
Yes — in Getxo (Bilbao) you need a recreational sea-fishing licence (issued by the autonomous community); breath-hold only (no scuba), with a marker buoy and no night diving. See the guide.
✓There is no fixed national catch cap (, art. 5 delegates it to the communities); the standard is 5 kg/person/day, with 1 specimen allowed not to count (Canaries — Decreto 182/2004, art. 38.3; Murcia; Galicia; Basque Country). Protected species have per-piece quotas.
✓Only a harpoon is allowed — hand-held or mechanically propelled, with one or several points (, art. 14.1). Carrying spearfishing gear and underwater breathing equipment aboard AT THE SAME TIME is prohibited (art. 14.2) — an offence in itself, even if you dived on a breath hold.
✓Spain is not one jurisdiction. The licence is issued by a coastal autonomous community, and you must comply with the rules of the administration on whose littoral you are in the water: «debiendo cumplir la normativa establecida por la administración en cuyo litoral se realice la actividad» (, art. 13). Interior waters — inside the straight baselines: bays, coves, rías, the whole coastal strip — are the community's competence; exterior waters are the State's. So the age, the days of the week, the distances and the are found in your community's act, not in the state one.
✓Basque Country: the spearfishing licence is issued by the Basque Government — Gobierno Vasco (Eusko Jaurlaritza): Decreto 198/2000, platform, spearfishing valid 1 year.
✓Basque Country: spearfishing needs a SEPARATE licence (Decreto 198/2000, art. 4); it takes being 16, an official sports medical certificate of fitness for this very activity, and accident + civil-liability insurance (art. 7.3). The cap is 5 kg (art. 12.1). Barred within 250 m of properly delimited bathing or watersport areas (art. 14.3); orto to ocaso only (art. 16). Ports, docks, habitual anchorages, navigation channels and vessel-traffic zones are closed; and a biotope, a special-protection zone or an artificial reef closes spearfishing only when ITS OWN norm says so (art. 18).
⛔ Seahorses (Hippocampus) — protected (RPE).
Rules change and are REGIONAL. Before heading out, check with the competent autonomous community (licence) and the min-size table in force.
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