Bow and Transom

A weekly for recreational boaters

Issue No. 1Week of October 26, 2026Free to read

Great Lakes & Inland

Great Lakes water levels for September 2026

Monthly means from NOAA, compared by code, and the open-lake forecasts as issued.

Built by code from the sources listed, no AI

Issue No. 1 · Published Tue Oct 27, 2026, 6:28 PM EDT · the whole issue

Lake Superior at Duluth: the September 2026 mean was 602.336 feet above IGLD 1985, 0.013 ft (0.2 in) lower than August 2026 (602.349 ft), and 0.010 ft (0.1 in) higher than September 2025 (602.326 ft).1 Lake Michigan at Milwaukee: the September 2026 mean was 579.436 feet above IGLD 1985, 0.170 ft (2.0 in) lower than August 2026 (579.606 ft), and 0.640 ft (7.7 in) higher than September 2025 (578.796 ft).2 Lake Huron at Harbor Beach: the September 2026 mean was 579.245 feet above IGLD 1985, 0.253 ft (3.0 in) lower than August 2026 (579.498 ft), and 0.613 ft (7.4 in) higher than September 2025 (578.632 ft).3 Lake Erie at Cleveland: the September 2026 mean was 572.077 feet above IGLD 1985, 0.131 ft (1.6 in) lower than August 2026 (572.208 ft), and 0.489 ft (5.9 in) higher than September 2025 (571.588 ft).4 Lake Ontario at Oswego: the September 2026 mean was 246.378 feet above IGLD 1985, 0.574 ft (6.9 in) lower than August 2026 (246.952 ft), and 1.253 ft (15.0 in) higher than September 2025 (245.125 ft).5

The open-lake forecasts, as issued

Forecasts change several times a day. Check the current NWS marine forecast before you go out. Each synopsis below is quoted word for word from the National Weather Service.

Lake Superior National Weather Service Marquette MI, issued 400 PM EDT Tue Oct 27 2026. Archived text · Current forecast6

30.5 inch high pressure centered over northern Ontario this morning shifts east to the Saint Lawrence Seaway this evening, with 30.4 inch ridging over Lake Superior weakening to 30.1 inches through tonight. A developing 29.8 inch Colorado low lifts through the Plains on Wednesday, eventually moving across Lake Superior Wednesday night into early Thursday morning. High pressure of 30.2 to 30.3 inches returns to the Upper Great Lakes by Friday, strengthening to 30.4 inches over the Lower Great Lakes on Saturday as ridging of 30.1 to 30.2 inches lingers over Lake Superior through the weekend.

Lake Michigan National Weather Service Milwaukee/Sullivan WI, issued 237 PM CDT Tue Oct 27 2026. Archived text · Current forecast7

High pressure of 30.5 inches will continue to work east across Ontario this afternoon and move over New England by Wednesday morning. Meanwhile, broad low pressure of 29.8 inches will move into the central to northern Great Plains. Moderate southeast winds will continue through this afternoon and evening, with winds remaining elevated and becoming southerly during the pre- dawn hours on Wednesday. Elevated southerlies persist Wednesday, and will become gusty Wednesday night ahead of an approaching cold front. Gusts will stop a couple knots short of gales over the northern end of Lake Michigan, though a few intermittent gusts to gale force can`t be ruled out. Winds then become southwesterly and come around to northwesterly following the front. Winds then quickly slow behind the front Thursday afternoon and evening as high pressure of 30.2 inches works in from the central plains.

Lake Huron National Weather Service Detroit/Pontiac MI, issued 339 PM EDT Tue Oct 27 2026. Archived text · Current forecast8

High pressure, 30.50 inches, will settle over southern Quebec this evening. Low pressure is forecast to move across northern Ontario into Quebec on Thursday, dragging a cold front across the Great Lakes. This front will provide the next chance for light rain.

Lake Erie National Weather Service Cleveland OH, issued 337 PM EDT Tue Oct 27 2026. Archived text · Current forecast9

High pressure 30.50 inches will move off to the New England Coast Wednesday. A cold front slides south across Lake Erie Thursday night. High pressure of 30.40 inches will build over the eastern Great Lakes again Friday into Saturday before a warm front lifts north across the lake on Sunday.

Lake Ontario National Weather Service Buffalo NY, issued 402 PM EDT Tue Oct 27 2026. Archived text · Current forecast10

A ridge averaging 30.6 inches affects the lake through Thursday as the embedded high pressure center wobbles southeastward from northern Ontario to North Atlantic waters southeast of the Canadian Maritimes. The ridge exits eastward Thursday night as a cold front sweeps eastward across the lake. Behind the front, another ridge averaging 30.2 inches builds from the western Great Lakes through this Saturday. The high will drift eastward while a 29.9 inch low is expected to move into the Lower Mississippi Valley Sunday.

Sources

Each sentence above is numbered to the source it was written from. Facts, numbers, names and dates come from these sources and were checked against them by code before publishing; the check is narrow and cannot judge every meaning, so read the sources for anything that matters. The official text governs. U.S. government sources have an archived copy of the exact text used.

  1. Bow and Transom, computed from NOAA CO-OPS data Lake Superior at Duluth: monthly mean water levels compared Computed October 27, 2026 Fetched Tue Oct 27, 2026, 6:28 PM EDT Archived copy Lake Superior at Duluth: the September 2026 mean was 602.336 feet above IGLD 1985, 0.013 ft (0.2 in) lower than August 2026 (602.349 ft), and 0.010 ft (0.1 in) higher than September 2025 (602.326 ft). Computed by Bow and Transom from the monthly means of NOAA station 9099064 (NOAA CO-OPS). Formula: difference = later mean minus earlier mean, in feet as given; inches = feet x 12, rounded to 1 decimal. Latest NOAA reading (preliminary): 602.231 ft at 2026-10-27 22:18 GMT. Computed by Bow and Transom from NOAA CO-OPS station 9099064 (Duluth), feet above IGLD 1985.
  2. Bow and Transom, computed from NOAA CO-OPS data Lake Michigan at Milwaukee: monthly mean water levels compared Computed October 27, 2026 Fetched Tue Oct 27, 2026, 6:28 PM EDT Archived copy Lake Michigan at Milwaukee: the September 2026 mean was 579.436 feet above IGLD 1985, 0.170 ft (2.0 in) lower than August 2026 (579.606 ft), and 0.640 ft (7.7 in) higher than September 2025 (578.796 ft). Computed by Bow and Transom from the monthly means of NOAA station 9087057 (NOAA CO-OPS). Formula: difference = later mean minus earlier mean, in feet as given; inches = feet x 12, rounded to 1 decimal. Latest NOAA reading (preliminary): 579.173 ft at 2026-10-27 22:18 GMT. Computed by Bow and Transom from NOAA CO-OPS station 9087057 (Milwaukee), feet above IGLD 1985.
  3. Bow and Transom, computed from NOAA CO-OPS data Lake Huron at Harbor Beach: monthly mean water levels compared Computed October 27, 2026 Fetched Tue Oct 27, 2026, 6:28 PM EDT Archived copy Lake Huron at Harbor Beach: the September 2026 mean was 579.245 feet above IGLD 1985, 0.253 ft (3.0 in) lower than August 2026 (579.498 ft), and 0.613 ft (7.4 in) higher than September 2025 (578.632 ft). Computed by Bow and Transom from the monthly means of NOAA station 9075014 (NOAA CO-OPS). Formula: difference = later mean minus earlier mean, in feet as given; inches = feet x 12, rounded to 1 decimal. Latest NOAA reading (preliminary): 578.648 ft at 2026-10-27 22:18 GMT. Computed by Bow and Transom from NOAA CO-OPS station 9075014 (Harbor Beach), feet above IGLD 1985.
  4. Bow and Transom, computed from NOAA CO-OPS data Lake Erie at Cleveland: monthly mean water levels compared Computed October 27, 2026 Fetched Tue Oct 27, 2026, 6:28 PM EDT Archived copy Lake Erie at Cleveland: the September 2026 mean was 572.077 feet above IGLD 1985, 0.131 ft (1.6 in) lower than August 2026 (572.208 ft), and 0.489 ft (5.9 in) higher than September 2025 (571.588 ft). Computed by Bow and Transom from the monthly means of NOAA station 9063063 (NOAA CO-OPS). Formula: difference = later mean minus earlier mean, in feet as given; inches = feet x 12, rounded to 1 decimal. Latest NOAA reading (preliminary): 571.565 ft at 2026-10-27 22:18 GMT. Computed by Bow and Transom from NOAA CO-OPS station 9063063 (Cleveland), feet above IGLD 1985.
  5. Bow and Transom, computed from NOAA CO-OPS data Lake Ontario at Oswego: monthly mean water levels compared Computed October 27, 2026 Fetched Tue Oct 27, 2026, 6:28 PM EDT Archived copy Lake Ontario at Oswego: the September 2026 mean was 246.378 feet above IGLD 1985, 0.574 ft (6.9 in) lower than August 2026 (246.952 ft), and 1.253 ft (15.0 in) higher than September 2025 (245.125 ft). Computed by Bow and Transom from the monthly means of NOAA station 9052030 (NOAA CO-OPS). Formula: difference = later mean minus earlier mean, in feet as given; inches = feet x 12, rounded to 1 decimal. Latest NOAA reading (preliminary): 245.052 ft at 2026-10-27 22:18 GMT. Computed by Bow and Transom from NOAA CO-OPS station 9052030 (Oswego), feet above IGLD 1985.
  6. National Weather Service Open Lake Forecast for Lake Superior Issued 400 PM EDT Tue Oct 27 2026 Fetched Tue Oct 27, 2026, 6:27 PM EDT Archived copy
  7. National Weather Service Open Lake Forecast for Lake Michigan Issued 237 PM CDT Tue Oct 27 2026 Fetched Tue Oct 27, 2026, 6:27 PM EDT Archived copy
  8. National Weather Service Open Lake Forecast for Lake Huron Issued 339 PM EDT Tue Oct 27 2026 Fetched Tue Oct 27, 2026, 6:27 PM EDT Archived copy
  9. National Weather Service Open Lake Forecast for Lake Erie Issued 337 PM EDT Tue Oct 27 2026 Fetched Tue Oct 27, 2026, 6:27 PM EDT Archived copy
  10. National Weather Service Open Lake Forecast for Lake Ontario Issued 402 PM EDT Tue Oct 27 2026 Fetched Tue Oct 27, 2026, 6:27 PM EDT Archived copy

Spotted an error? Tell us through weldonpc.com/contact, with the issue number and the sentence.