Today — right on the edge — 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 Detroit, we'll send the go / no-go verdict. Email is all we need.
Every covered town has its own live forecast, cameras and entry points. Choose where you're diving.
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: 1391 spots across 205 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 mapShoal on the line of the vanished Mamajuda Island in the lower Detroit River, about 8 m. Hard bottom and old crib remains in the current; drift dive with a live boat, and stay clear of the Livingstone shipping channel.
Google MapsNamed mid-river bar at the head of the Detroit River, about 8 m over hard bottom with the whole outflow of Lake St. Clair running across it. A live-boat drift only; visibility is poor most of the year and traffic is heavy.
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.
Check the cam BEFORE you leave. Foam, brown/green murk, or waves washing the entry rocks = No-go. At night/in fog the cam is useless — treat it as «unknown», NOT «green».
Detroit sits on the connecting water between Lake St. Clair and Lake Erie: strong current, a working shipping channel and the largest market in the region. Visibility is usually poor, though there is submerged structure off Belle Isle, and no confirmed dive site came out of this research pass — treat the city as a forecast node rather than a destination. The 2026 regulations name the waters where lake trout, northern pike and walleye may be taken with an underwater spear, and this water is not among them. Freedive only, daylight only, and a free underwater spearfishing licence on top of the fishing licence, with no monthly reporting since the 2026 season.
Depths below are the published site depths, not a promise about conditions. Outside the buoyed preserve sites you find the mark yourself.
| Spot | Type | Depth | Level | Access | Notes |
|---|---|---|---|---|---|
| Scott Middle Ground | Mid-river bar | 5–8 m | Advanced, live-boat only | Drift at the head of the river | Named mid-river bar at the head of the Detroit River, hard bottom with the whole outflow of Lake St. Clair running across it. A live-boat drift only; visibility is poor most of the year and traffic is heavy. |
| Mamajuda Island Shoal | Shoal | 5–8 m | Advanced, live-boat only | Drift in the lower river, off the shipping channel | Shoal on the line of the vanished Mamajuda Island in the lower Detroit River. Hard bottom and old crib remains in the current — drift with a live boat and stay clear of the Livingstone shipping channel. |
SpainUS spearfishing law is state-by-state. License, spearable species, powerhead rules and distances vary; federal sanctuaries (Gray's Reef, the Keys, Flower Garden Banks) ban spearfishing. Always confirm with the state agency and local ordinances.
Yes, but narrowly. Michigan's Lake Huron game-fish zone stops at the mouth of the St. Clair River, and Lake St. Clair, the St. Clair River and the Detroit River are connecting waters outside it. So no lake trout, northern pike and walleye by underwater spear at Detroit — only the year-round list — and muskellunge may not be taken by any means other than hook and line on Lake Erie, Lake St. Clair, the Detroit River and the St. Clair River. The instrument is the Bow & Spear Fishing Regulations table of the Michigan Fishing Guide, a Fisheries Order under NREPA Part 487.
The year-round Michigan list is the backbone: bowfin, bullheads, burbot, common carp, catfish, cisco, freshwater drum, gizzard shad, goldfish, grass carp, longnose gar, rainbow smelt, suckers and lake whitefish. On these lakes whitefish, cisco and burbot are real targets on it, not a consolation prize. Lake sturgeon is off the table: spearing it is prohibited except in a special Black Lake winter season, and on every water here it is closed or release-only. Michigan's table is an enumerating one: trout and salmon other than lake trout, bass, sunfishes and crappie are not named, so they are not open.
Two licences, not one. You need the Michigan All Species fishing licence — 26 USD resident, 76 USD non-resident, 10 USD a day, from age 17 — plus a free annual underwater spearfishing licence, which is mandatory — though its monthly effort-and-harvest report was abolished for the 2026 season. The gear rules are just as concrete. A rubber- or spring-propelled spear may be fired only while you are fully submerged, and it must be tethered to a line no longer than 20 ft. Scuba and rebreathers are prohibited while underwater spearfishing, so this is a freedive discipline. Daylight only, bands unloaded whenever you move between areas, and 150 ft off swimming areas, docks, boat access sites and power intakes — which effectively closes harbour mouths.
Lake St. Clair and the St. Clair and Detroit rivers freeze from December to March, and frazil ice in the current is genuinely dangerous. The workable season is May to November. Plan for a thick suit with hood, gloves and boots, or a drysuit: the thermocline shapes every dive here, and what feels workable at the surface is a different lake ten metres down. There is no tide on the Great Lakes — the level moves with wind and pressure.
Cold is the first risk and it is not seasonal: below the thermocline the water stays a few degrees above freezing all summer, and the freedive-only rule leaves you no gas reserve to buy time with. The second is current. These are connecting waters carrying the outflow of a whole lake through a narrow section, so the river sites are live-boat drifts, not anchored dives, and commercial traffic runs through the same water: keep a diver-down flag up where it does not block navigation, and stay out of the shipping channel. Finally, ice: the water freezes for months, and frazil and shore ice make the shoulder seasons a different sport.
No. Michigan's 2026 underwater-spear permission is a list of named waters and this one is not on it, so what is open here is the year-round list — whitefish, cisco, burbot and the rough fish.
No. Scuba, rebreathers and similar devices are prohibited while underwater spearfishing: Michigan is freedive-only.
The Michigan All Species fishing licence plus a free annual underwater spearfishing licence, whose mandatory monthly effort-and-harvest report was abolished for the 2026 season.
No. It is prohibited from 30 minutes after sunset to 30 minutes before sunrise, and you must stay 150 ft off swimming areas, docks, ramps and power intakes.
Only as a live-boat drift, and only for experienced divers. The river carries the outflow of a whole lake through a narrow section and commercial traffic uses the same channel.
Lake St.
Portugal
