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
calmupdated 11:44
Viana do Castelo — solo, off the rocks
DON'T GO
⛔ Banned here
don't go · wave 1.3 m (occasionally up to ~2.6 m)
wave 1.3 mwind 16, gusts 34 km/hsurge pounding the rocksvisibility ~1 m
today, best window 12:00–15:00
fish · Visibility 1 m · Water 16.2°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.
Wednesday · today2026-09-09
07:09–19:55 · new moon
▲ 02:00▼ 08:00▲ 14:00▼ 20:00 · 3.0 m
Hours (06→20)
06
09
12
15
18
Day's trends
Tide-0.83 m
Wave1.32 m
Wind7 km/h
Water15 °C
fish activity: moonrise 05:01 · moderate · moon overhead 12:10 · high · moonset 19:07 · moderate · moon underfoot 00:00 · high
Conditions window12:00–15:00
don't go fish ·
Hs 1.32 m · roughperiod 7.2 swind 16→34surge 6.6viz 1 m
1.32 mrough · up to ~2.64 · 315° at an angle
7.2 sswell moderate
16→34gusts 34 km/h
6.6pounding the rocks
0.36m/s
1 mrecent swell
16.2°C5 mm + hood
▲14:00tide turn near
Atmosphere40 kmlandmarks visible
highmoon overhead
wave 1.3 m (occasionally up to ~2.6 m)
steep wind-wave — choppy surface, careful on entry
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: 1391 spots across 205 stretches of coast — mainland Portugal, Madeira and the Azores.
Early morning before bathers, and outside bathing season (1 May–31 Oct), when hunting is banned by the beach. Warmest water — late summer.
tide
High water: the tidal platforms and pools fill and you can get past the barrier; at low tide it all dries out with no water to swim.
shelter
The nearshore rock barrier breaks the bigger waves — the most sheltered entry in the area. Shielded from moderate NW swell, but not from due-west swell.
conditions
Diveable more often than the exposed points thanks to the rock barrier: swell up to ~1.5 m, light E/NE wind. Visibility swings with sediment from the pools and weed.
hazard
The dominant danger is entrapment/impact on the barrier rocks as swell builds: it's calm inside, but on the barrier crest the wave throws you onto sharp rock. Urban beach — many bathers.
access
In town, by the Forte da Areosa (Castelo Velho); parking close, to the water across the rock platforms. Rocks slippery with weed.
Known OWD dive site 'Pedras Ruivas' — octopus, wrasse, fish in holes. The beach core is concessioned/lifeguarded: hunting banned by the beach in season, hunt on the reefs to the side.
Early morning, flat sea, late spring to early autumn. Quiet rocky shore within Areosa.
tide
High/incoming water — covers the rocks and reef; at low tide little water and sharp rocks on the exit.
shelter
Small cove with a rock barrier that breaks the main swell — a relatively sheltered entry. Wind-shielded by the rocks, but not from large west swell.
conditions
On swell up to ~1.2–1.5 m and E/NE offshore. Fewer people than Praia Norte, but no oversight either — the window is just as narrow.
hazard
Same pattern as Praia Norte: barrier rocks and shorebreak on the exit as swell builds; entrapment between blocks. Cold water, nobody around — solo is risky.
access
Off EN13 in Areosa to the small cove; short path to the rocks. Limited parking, rocky entry — reef boots essential.
Rocky cove with almost no sand and a natural breakwater — a quiet alternative to Praia Norte in the same rocky sector south of Montedor.
Early morning and OUTSIDE bathing season (1 May–31 Oct) — in summer it's a concessioned lifeguarded beach, hunting banned at the beach and 300 m in front of it.
tide
High/incoming water on the rocky ends — fish move to the rocks; at low tide there's nothing on the open sand.
shelter
Sandy bay with rocks at the ends gives partial wind cover; this is already the sandy sector north of the headland — open to direct NW swell.
conditions
Only diveable on a flat sea with swell <1 m: hunt the rocky ends of the bay, the centre is fishless sand. Cold water; sand clouds visibility in any swell.
hazard
Exposed sandy beach = pronounced shorebreak and rip currents by the rocky ends in any swell; no reference points on sand and it drags you fast. Highest solo severity of the four.
access
Via EN13, turn to Praia do Paçô (~10 km from Viana), large car park (350 spaces), to the water on boardwalks. Hunt off the rocks at the ends, not from the centre of the beach.
Guides list the beach for line and spear fishing, but it's a lifeguarded beach: the main water is protected in season. For a solo beginner — scout from land only, hunt the rocky ends out of season.
Montedor Promontory / Praia de FornelosMontedor headland, Carreço · Promontório de Montedor / Praia de Fornelos
dangerous
best candidate for today
exposed head-on to the swell today
window
Early morning on a flat sea, late spring to early autumn (warmer water, bathing season). In winter swell shuts the point down nearly always.
tide
Incoming / high water: the submerged rocks cover and fish move onto the platform; at low tide the rocks dry out and entry gets dangerous.
shelter
The rocky outcrops around the headland give some cover from N wind; against direct NW swell there is no shelter — this is an exposed Atlantic point.
conditions
Only in a small window: swell under ~1–1.2 m and light E/NE (offshore) wind. The north coast is cold and often turbid — you need a sustained flat, calm spell.
hazard
The dominant danger is building NW swell breaking on the outcrops: you enter calm, but the rocky exit in the shorebreak becomes a trap. Cold water and current running along the point. Boat traffic further out.
access
EN13 to Montedor/Carreço, then toward the lighthouse and down the Geoparque trail to the rocks by Praia de Fornelos. Enter off the rocks between the lighthouse and the sand — slippery, reef boots essential.
Montedor promontory is the boundary: sand to the north, rocky coast to the south. The area's best rocky reef (sea bass, bream, conger in holes), but exposed — scout from land first.
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.
In season now: Sea bass, White seabream, Gilthead bream, Salema, Octopus, Mullet
In season now
Robalo (sea bass)
<4 m · end of ebb → start of flood · dawn/dusk
Prime target. Shy of light — pick early/twilight windows.
Sargo (white seabream)
1–5 m · flood (rides the surf onto the reef) · dawn
Dominant reef target. Visibility matters more than time of day.
Dourada (gilthead bream)
1–4 m · flood over sand/weed · dawn
Very skittish — static ambush.
Salema
0–2 m · — · daytime
Easiest target at 0–6 m. ⚠️ Do NOT eat the head/guts (ichthyosarcotoxism).
Polvo (octopus)
1–6 m · high water · twilight
Peaks in autumn. Spot the den by the pile of shells. Don't take egg-bearing females. Min. weight 750 g (DGRM).
Tainha (mullet)
0–2 m · — · —
Extremely wary; murky water HINDERS it. Opportunistic, in calm coves.
Santola (spider crab)
1–10 m · low water (reef shelf exposed) · calm morning (≤force 2)
Carapace ≥12 cm. Peaks Jul–Aug. CLOSED 15.02–15.06. Limit 2 kg/day.
Law
🦀 spider crab open (season 16.06–14.02)
✓Spearfishing licence required, daily/monthly/annual (~€25/yr). Speargun = licence required. (DL 246/2000, art. 12.º + 12.º-A; fees in , .) There is no minimum age for the licence, but under-16s are exempt from holding one when fishing accompanied by a licence holder (art. 12.º n.º 2 al. b).
✓Hand-gathering shellfish with NO gear — no licence; but if a speargun is on the dive, a spearfishing licence is required (DL 246/2000, art. 12.º n.º 1; ).
✓Night prohibited: spearfishing only in daylight (sunset→sunrise not allowed). Artificial light as a means of finding/attracting fish is banned — a torch for safety only (, art. 8.º/3 + 3.º/5; DL 246/2000, art. 14.º n.º 1 d).
✓Signalling buoy MANDATORY for spearfishing: buoy/float with an «Alfa» flag (red/orange/yellow, ≥8 L), no more than 30 m from the diver (, art. 4.º/2).
✓Spearfishing daily limit: fish + cephalopods — 15 kg (excluding the largest specimen). General rod-and-line recreational fishing — 10 kg (, art. 12.º/1).
✓Spider crab: min. carapace 12 cm; (closed season) 15.02–15.06 — applies to recreational gathering too (, ; table).
✓Min. sizes: robalo 36 cm, sargo 17 cm, dourada 19 cm, choupa 23 cm, corvina 42 cm; octopus 750 g ( + EU Reg. 2019/1241; minimum-size table).
✓Grouper — fully protected, may not be taken (
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. At Cabo Raso/Arriba a 0.5 m rise in swell makes a boulder exit impossible — getting pinned/unable to climb out is the main killer here.
Headland rip: at Cabo Raso there is 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.
Nortada (Jun–Sep): wind builds from midday — be out of the water by ~11:00; 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.
Local guide · Viana do Castelo
Spearfishing in Viana do Castelo: spots, seasons and rules
Updated 2026-07-09 · By Oleksandr, spearfisher
Spearfishing in Viana do Castelo is possible, but only when the exposed northwest coast settles. The useful ground is rocky: Montedor for the strongest reef, Pedras Ruivas for the most sheltered urban entry, and Porto de Vinha for a quieter cove. Cold water, low visibility after swell, slippery exits and building NW surf are the main limits. Treat it as an intermediate north-Portugal spot, not a first solo dive.
TL;DR
Viana do Castelo is a cold, exposed north-coast window, not a casual beginner shore dive.
Look for rock at Montedor, Pedras Ruivas and Porto de Vinha; avoid scout-only Paçô as a recommendation.
Best odds are early summer mornings, small swell, light E or NE wind and a rising tide.
Best spearfishing spots in Viana do Castelo
These are the usable, non-scout entries for this coast. All still need a land check before you suit up.
Spot
Type
Depth
Level
Access
Notes
Montedor Promontory / Praia de Fornelos
Exposed rocky headland
Shallow to mid reef
Intermediate to advanced
EN13 to Montedor/Carreço, then the Geoparque trail down to the rocks
Best reef structure for bass, sargo and holes, but the rocky exit closes fast on NW swell.
Pedras Ruivas (Praia Norte)
Nearshore rock barrier
Shallow pools and platforms
Intermediate
Praia Norte seafront by Forte da Areosa
More sheltered than the points, but crowded and seasonal beach rules matter.
Praia do Porto de Vinha
Small rocky cove
Shallow reef edges
Intermediate
Short path from Areosa off the EN13
Quieter than Praia Norte, with a natural breakwater. Still risky solo if the swell builds.
When are Viana do Castelo conditions worth it?
Aim for late spring to early autumn, early morning, a flat or fading sea and light E/NE offshore wind. Montedor wants swell around or below 1 to 1.2 m; the Areosa coves can be slightly more forgiving, but visibility still drops after rough water. Incoming or higher tide covers the slabs and lets fish move onto the reef. Low water exposes rocks and makes exits sharper.
✓Breath-hold only: spearfishing may be practised in apnea alone. Scuba, rebreather and hookah are banned; the speargun may not be powered by a detonating charge or by compressed gas (DL 246/2000, art. 9.º n.º 3 — o antigo art. 6.º foi revogado).
✓The catch may NOT be sold: displaying for sale, offering or selling recreational catch is prohibited — it is for the fisher, the household, or donation to charitable, scientific or museum institutions (DL 246/2000, art. 7.º).
✓A loaded speargun out of the water is an offence (DL 246/2000, art. 14.º n.º 2 f). Same article: no fishing closer than the legally set distance from concessioned beaches during the bathing season (n.º 2 d), nor in places closed for health or marine-traffic reasons (n.º 2 e). The exact metres come from the regulation and the capitania — check before you go.
✓Distances between people: at least 20 m from another spearfisher (, art. 6.º n.º 3) unless you agree otherwise; from a boat, 50 m from other vessels, divers and set gear (art. 6.º n.º 2); every vessel must keep 50 m from your signalling buoy and from boats flying flag Alfa (art. 7.º n.º 6). The figure that circulates — «30 m between hunters» — is wrong: 30 m is the distance to YOUR OWN buoy.
✓What you may take into the water: the CAPTURE gear on a spearfishing dive is the speargun, a shellfish knife, a gaff (puxeiro) and an arrelhada (, art. 3.º n.º 3). That is not a ban on everything else: art. 4.º n.º 1 expressly allows equipment for cold protection, for buoyancy, for protection or safety and for carrying the catch, and any other equipment that does not permit the direct capture of specimens. Bait and groundbait are PROHIBITED in spearfishing (art. 5.º n.º 3). You may not carry or keep a speargun and a breathing apparatus aboard at the same time, nor carry the gun ready to fire out of the water or in a zone where spearfishing is banned (art. 3.º n.º 6). On any recreational-fishing boat the whole crew wears a lifejacket (art. 4.º n.º 3).
✓Where recreational fishing is closed altogether (, art. 8.º n.º 1): in marked shipyard zones (no exception) and in aquaculture establishments — in the LATTER only, fishing is possible when the concession-holder or owner formally authorises it; the shipyard bar has no such carve-out; within 100 m of the mouth of any marked sewage outfall; over beach-concession waters, to the extent the POOC sets; and in other zones closed by the port or maritime authority. For spearfishing and boat fishing specifically (n.º 2) the navigation channels of port and river bars, the approach channels and the buoyed channels are closed. There is NO «300 m from the beach» rule on the mainland — that number comes from Madeira's own act; on the mainland the distance is set by the POOC and by the capitania's edital.
✓The border rivers Minho and Guadiana: spearfishing is BANNED along both international stretches — bilateral Portugal-Spain agreements, art. 9.º n.º 3 (Minho, RAR 34/2023, in force since 26-05-2023) and art. 6.º n.º 1 (Guadiana, RAR 173/2025, in force since 07-12-2025), both reading «É proibida a pesca submarina». On the Guadiana it is also a serious offence (art. 19.º), and a 100 m strip alongside the Sapal de Castro Marim reserve is closed separately (art. 5.º). The stretches run from the confluence with the Trancoso / the Chança down to the closing line at each mouth.
✓On the other Portuguese-Spanish border river stretches (outside the TIRM and the Guadiana maritime-jurisdiction zone) — Decreto 30/88, art. 6.º n.º 1: harpoons, gigs, tridents and any blunt instrument used to take fish are prohibited (al. e), as is «a pesca ou caça subaquática» with artificial light, and night fishing (al. g).
Portugal
Spain