Maine boating conditions

Casco Bay marine forecast

Start with Portland Harbor, then compare nearby Maine coast briefings for a wider read on the day.

Tonight: Casco Bay E 5 kt, seas 2–3 ft. Best day this week: Fri, Nov 6. Fri, Nov 6 is the mildest day in the forecast. It is still Nope on at least one period.

REST OF TODAYNOPE3 of 3 harbors reporting

NWS MARINE ADVISORIESNone activeANZ153

Boat 0Caution 3Nope 0

Forecast checked Fri, Nov 6, 2026, 7:24 PM EST · National Weather Service coastal waters forecast issued 5:01 PM EST · harbor briefings updated 7:24 PM EST · water temperature updated 7:18 PM EST

Right now

Casco Bay conditions today

Each flag is that harbor's live call. Zone labels use the coastal waters forecast for the rest of today.

Boat Caution Nope

PortlandN 4 kt gust 8
Western Maine ShelfS 12 kt gust 14

NWS coastal waters forecast

Casco Bay forecast by zone

Each period is scored with the same limits as the harbor pages: 15 kt wind, 20 kt gusts, 2.5 ft seas. Thunderstorms or reduced visibility turn a period to Caution.

FriNov 6Best day

DayNight

SatNov 7

DayNight

SunNov 8

DayNight

MonNov 9

DayNight

TueNov 10

DayNight

Casco Bay

The bay itself. Neighboring harbors stay on the cards below

No advisory

—Unavailable

NopeE 5 kt2–3 ftbecoming NE late this evening and early morning, then becoming N towards daybreak · thunderstorms · reduced visibility

NopeNE 10–15 kt · gusts 202–3 ftShowers

NopeN 10–15 kt · gusts 202–3 ftShowers

NopeNW 10–15 kt · gusts 202–3 ftShowers likely, mainly in the morning

NopeW 5–10 kt2–3 ft

NopeW 5–10 kt · gusts 202–3 ftincreasing to 10 to 15 kt with gusts up to 20 kt in the afternoon

NopeW 10–15 kt · gusts 202–3 ftdiminishing to 5 to 10 kt after midnight

NopeSW 5–10 kt2–3 ft

NopeW 5–10 kt2–3 ft

Casco BayNo advisory

Fri ★

—

Nope

—

Sat

Nope

NE 10–15 kt

Sun

Nope

NW 10–15 kt

Mon

Nope

W 5–10 kt

Tue

Nope

SW 5–10 kt

Official NWS text for each zone

Casco Bay (ANZ153)

Tonight: E winds around 5 kt, becoming NE late this evening and early morning, then becoming N towards daybreak. Seas 2 to 3 ft. Rain with a slight chance of tstms this evening, then rain after midnight. Patchy fog. Vsby 1 to 3 NM.

Sat: NE winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Showers.

Sat Night: N winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Showers.

Sun: NW winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Showers likely, mainly in the morning.

Sun Night: W winds 5 to 10 kt. Seas 2 to 3 ft.

Mon: W winds 5 to 10 kt, increasing to 10 to 15 kt with gusts up to 20 kt in the afternoon. Seas 2 to 3 ft.

Mon Night: W winds 10 to 15 kt with gusts up to 20 kt, diminishing to 5 to 10 kt after midnight. Seas 2 to 3 ft.

Tue: SW winds 5 to 10 kt. Seas 2 to 3 ft.

Tue Night: W winds 5 to 10 kt. Seas 2 to 3 ft.

Wed: W winds 5 to 10 kt. Seas 2 to 3 ft.

Wed Night: NW winds 5 to 10 kt. Seas around 2 ft. Winds and seas higher in and near tstms.

Five-day trend

Wind and seas across Casco Bay

Day and night bars for each zone, in the same wind and seas chart style as a harbor page. A missing bar is a period the forecast did not quantify.

Casco Bay

Wind0–15 kt

Dashed limit on the harbor pages: 15 kt. Bars are the top of the forecast range.

Seas0–3 ft

Dashed limit on the harbor pages: 2.5 ft. Bars are the top of the forecast range.

Harbor-level briefings

Compare conditions around Casco Bay

In Casco Bay

The current reviewed destination inside the bay.

MECautionPortland Harbor

Maine's largest harbor and the primary jumping-off point for the islands and passages of Casco Bay.

4 ktseas 2 ft53°F water

Conditions are Caution now, and seas exceed your 2.5 ft limit around 11 PM; plan to be back before then.

FrSaSuMoTuWeTh

Open marine conditions →

Nearby Maine coast

Useful neighboring briefings for broader coastal context.

MECautionKennebunkport

A lower Maine coast destination centered on the Kennebunk River and nearby Cape Porpoise anchorage.

12 ktseas 2 ft54°F water

Conditions are Caution now and remain evaluated through 11:24 PM.

FrSaSuMoTuWeTh

Open marine conditions →MECautionBoothbay Harbor

A sheltered Midcoast harbor known for island passages, busy summer docks, and nearby coves.

4 ktseas 2 ft53°F water

Conditions are Caution now, and seas exceed your 2.5 ft limit around 11 PM; plan to be back before then.

FrSaSuMoTuWeTh

Open marine conditions →

Tide charts

Tide charts around Casco Bay

Portland Harbor tide chart
CO-OPS 8418150
Low tide 2:20 AM · 0.34 ft · High tide 8:35 AM · 9.93 ft · Low tide 2:52 PM · 0.02 ft · High tide 9:04 PM · 9.43 ft
53.2°Fwater
Rye Harbor tide chart
CO-OPS 8418911
Low tide 2:28 AM · 0.43 ft · High tide 8:46 AM · 9.64 ft · Low tide 3:01 PM · 0.14 ft · High tide 9:16 PM · 9 ft
—water unavailable

The regional picture

One body of water. More than one kind of boat day.

Casco Bay’s islands and passages can provide shelter in one direction and open a long fetch in another. Portland is the current Boat or Nope destination inside the bay, so its harbor briefing is the best local starting point - not a claim that one station captures every cove.

For a wider coastal check, the nearby briefings add observations and outlooks to the southwest and east. More Casco Bay destinations can join this page as their source bindings and editorial review are completed.

Before leaving the dock

Three useful checks for Casco Bay

Use Portland Harbor as a starting point, then check sources closest to the route you plan to run.
Account for island shelter and exposure; conditions can change quickly around a headland or passage.
Keep the official coastal waters forecast and current observations in the final pre-departure check.

What this regional guide can - and cannot - do

These pages make it easier to compare the latest available forecast and observation inputs around Casco Bay. They are planning aids, not navigation or safety guarantees. Check the official coastal waters forecast, current observations and notices, local conditions, and your own boat and crew before departure.

See how Boat or Nope builds each call