Today — sit it out.
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 Duluth, 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 mapThe concrete north pier of the Duluth Ship Canal, walk-in from Canal Park with rock rubble and steel sheeting along its foot. Strong surge in any north-east wind and constant ship traffic. A viewing and snorkel line only - Minnesota does not authorise spear on Lake Superior.
Google MapsFirst iron-hulled Great Lakes bulk freighter, foundered 1915 and found in 1988; she rests upside down in 67 m with the stern buried in mud. Technical trimix dive off Knife River, calm mornings only. No spearfishing: Lake Superior is closed to spear in Minnesota.
Google MapsWhaleback steamer of 1892, cut down by a collision in 1902 and lying in 21 m less than a mile outside the Duluth Ship Canal. Boat dive on an exposed lake bed; cold, dark, best August-October. Minnesota authorises no spear on Lake Superior - dive only.
Google MapsBurned hull of the 1856 Civil War gunboat, beached and torched off Wisconsin Point in 1931; frames and iron lie in the surf zone in a few metres. Easy shore swim from the Superior side, flat water only. Wisconsin Outlying Waters rules apply, not Minnesota's.
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».
Spearfishing in Duluth is a clean no. Minnesota's Lake Superior rule, Minn. R. 6262.0300 subp. 1, says fish may not be taken in the lake except as that part provides, and the part authorises angling and smelt gear — never a spear, speargun or harpoon. The underwater harpoon rule, 6262.0600 subp. 1a A, is scoped to inland waters. Duluth is still worth the trip as a dive base: the Thomas Wilson sits in 21 m just outside the ship canal, the Onoko in 67 m, and the North Pier is a walk-in snorkel line. Bring a drysuit — below 15 m the water holds 4-7 °C all year.
This is a dive table, not a hunting table. Minnesota does not authorise a spear anywhere on its Lake Superior shore, so the useful facts here are wreck type, depth and access. Note the one boundary case: the USS Essex lies off Wisconsin Point, on the Wisconsin side, where a different rule book applies.
| Spot | Type | Depth | Level | Access | Notes |
|---|---|---|---|---|---|
| Thomas Wilson | Wreck | 21 m | Boat dive, advanced · dive only | Boat, under a mile outside the ship canal | The whaleback steamer of 1892, cut down in a collision in 1902 and lying in 21 m of exposed lake bed. Cold and dark; best August-October. Minnesota authorises no spear on Lake Superior. |
| Duluth Ship Canal North Pier | Jetty | 3-8 m | Snorkel and shallow scuba · dive only |
US 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.
| Walk-in from Canal Park |
| The concrete north pier with rock rubble and steel sheeting along its foot. Strong surge in any north-east wind and constant ship traffic. A viewing and snorkel line only. |
| USS Essex | Wreck | 1-4 m | Beginner shore swim · Wisconsin rules apply | Shore, Wisconsin Point | Frames and iron of the 1856 gunboat, beached and burned off Wisconsin Point in 1931, lying in the surf zone. It sits on the Wisconsin side, so the Outlying Waters rules apply, not Minnesota's. |
| SS Onoko | Wreck | 67 m | Technical trimix · dive only | Boat off Knife River | The first iron-hulled bulk freighter on the lakes, foundered in 1915 and found in 1988, upside down in 67 m with the stern buried in mud. Calm mornings only. |
No. Minn. R. 6262.0300 subp. 1 states that fish may not be taken in Lake Superior except as provided by that part or under permit, and the part goes on to authorise angling with up to two lines plus smelt by dip net and minnow seine. It authorises no spear, no speargun and no harpoon. Minnesota's own DNR, asked where a diver may spear or harpoon, answers "all inland waters" and does not name Lake Superior. There is an honest interpretive tail: subpart 6 lets other species be taken "as allowed by inland regulations", which read broadly might drag inland methods onto the lake. We publish the narrow reading — no spearfishing on Minnesota's Lake Superior — and treat the closure as advisory rather than a hard mapped ban, because a whole Great Lake should not be stamped red on a negative inference.
Inland, and only inland. Minn. Stat. 97C.371 subd. 1 is an exhaustive list: common carp, native rough fish, catfish, lake whitefish, cisco (tullibee) and northern pike. Subd. 2 then confines catfish, whitefish, cisco and pike to dark houses, which is an ice fishery. What is left for a diver is common carp and native rough fish — buffalo, sucker, redhorse, freshwater drum, bowfin, gar, goldeye, bullhead. Minn. R. 6262.0600 subp. 1a A allows those to be taken by harpooning with a rubber-powered, spring or compressed-air gun, from 1 May through the Sunday before the third Monday in February, sunrise to sunset, in all inland waters. The gear rules are strict: the equipment may not be used within 1,000 feet of an established swimming beach, may be discharged only when both gun and operator are entirely beneath the surface, and may not be carried cocked out of the water. The digest adds a 20-foot tether.
They close it further. Minn. R. 6262.0700 bars taking rough fish by spearing, harpooning, archery or dip netting in any designated trout stream or lake, any posted spawning area, and any water where spawning, trapping or hatchery work is under way. Essentially every North Shore stream between Duluth and Grand Portage is a designated trout stream, so the creeks that look like obvious spear water are the one place the rule is explicit. Minnesota also bans possessing or transporting white perch, ruffe, round goby, black carp, bighead, grass and silver carp — only common carp sits inside the spearable list, so the "shoot the invasives" framing that works in Wisconsin and Illinois is simply wrong here. Lake sturgeon needs a $5 tag and is not a spearable species at all.
Harbours and bays ice over from January to March. The dive season runs from late May to October and peaks in August and September, when the plankton has dropped and the visibility is at its best. The surface rarely passes 13-15 °C even at the height of summer, and below 15 m the water holds 4-7 °C all year round — that is a drysuit number, not a wetsuit number, and it does not soften in August. Lake Superior has no useful tide: the astronomical range on the Great Lakes is a few centimetres and NOAA publishes no tide predictions for these stations, so the water level you plan around is wind- and pressure-driven seiche, not a tide table. The NOAA gauge 9099064 sits right in Duluth.
For angling and for any lawful inland harpooning you need a Minnesota fishing licence: resident adult annual $25, non-resident annual $51, non-resident 24-hour $14, 72-hour $36, 7-day $43, plus a $10 trout/salmon stamp which Lake Superior angling requires. Do not buy the spearing licence expecting it to help — the $6 resident / $17 non-resident spearing licence is for dark-house work only; underwater harpooning of rough fish needs the ordinary angling licence. For gear, plan on a drysuit or a 7 mm semi-dry with hood and gloves, a reliable light for wreck depth, and a dive flag. Ship traffic through the canal is constant and the north pier takes heavy surge in a north-east wind.
No. Minn. R. 6262.0300 subp. 1 closes Lake Superior to any method the rule does not list, and it lists no spear, speargun or harpoon.
No. Minn. R. 6262.0600 subp. 1a A applies to inland waters only. The DNR's own answer to "where can I spear or harpoon?" is "all inland waters", and Lake Superior is not named.
Minn. Stat. 97C.371 lists common carp, native rough fish, catfish, lake whitefish, cisco and northern pike — and the last four only from dark houses, which is ice fishing, not diving.
No. Minn. R. 6262.0700 closes designated trout streams and posted spawning areas to spearing and harpooning, and nearly every North Shore stream is a designated trout stream.
The Thomas Wilson in 21 m outside the ship canal, the SS Onoko in 67 m off Knife River for technical teams, and the ship canal north pier as a shore snorkel.
The surface rarely passes 13-15 °C and below 15 m it stays 4-7 °C year round. Harbours ice over from January to March.
A fishing licence is for taking fish. Since no lawful spear fishery exists here, plan around the dive rules; for angling, a Minnesota licence is $25 resident and $51 non-resident annually, plus the $10 trout/salmon stamp.
No. It lies off Wisconsin Point on the Wisconsin side, so Wisconsin's Outlying Waters rules govern it, not Minnesota's.
