Portsmouth, NH to Portland Harbor, ME map preview
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Portsmouth, NH to Portland Harbor, ME Marine Weather Route Forecast

Popular leg for cruisers heading into the Gulf of Maine.

Latest Automated Forecast

Optimized for marine passage planning, vessel routing, and coastal or offshore weather tracking. This automated marine weather routing tool updates daily using premium data models. Below is the weather, wave, and ocean current layout for a standard vessel transit from Portsmouth, NH to Portland Harbor, ME.

Generated: 2026-09-11T10:40:09.831607+00:00 • Distance: 54.2 NM • Departure: 2026-09-11T08:00:00-04:00 • Speed: 6 knots
Time Wind Waves Ocean Current Air/Water
2026-09-11T12:00:00+00:00 5.561557100000001 kts 0.22 m 0.2 kts N N 16.3 / 17.2 °C
2026-09-11T16:00:00+00:00 9.3412561 kts 0.38 m 0.3 kts N N 18.1 / 17.8 °C
Locked forecast rows are available to signed-in users.

Route Passage Summary & Sea State

Expect significant time on the nose, expect a more demanding trip. Winds range from 6 to 9 kts with waves 0.7 to 1.9 ft with period of 5 to 8 seconds. Overall, seas and wind frequently opposed, expect confused motion. Wind angles: 50% reaching, 50% on the nose. Sea state: 100% opposed.

More Detail

Points of Sail

CategoryPoint of SailWind AnglePortion of Passage
On the NoseNo-Go Zone0–45°50%
ReachingClose Hauled45–80°0%
ReachingBeam Reach80–110°25%
ReachingBroad Reach110–145°25%
FollowingRun145–180°0%

Sea State & Wave Motion

Sea StateWind vs. WavesBoat MotionPortion of Passage
AlignedWaves run with the windSteady, organized0%
Cross SeasWaves cross the windRolling0%
OpposedWaves against the windChoppy, confused100%
Historical Forecasts Download GPX File

Related Routes

Portland Harbor, ME to Portsmouth, NH
53.8 NM 14 waypoints
Boothbay Harbor, ME to Portland Harbor, ME
33.9 NM 10 waypoints
Provincetown Harbor, MA to Portland Harbor, ME
105.8 NM 10 waypoints
Gloucester, MA to Portsmouth Harbor Inlet, NH
35.9 NM 8 waypoints

Navigation Responsibility

This forecast is for informational purposes only. You are responsible for your own navigation and safety at sea. Always verify weather conditions with official sources, maintain a proper watch, and exercise prudent seamanship. Do not rely solely on this forecast for critical navigation decisions. See our Terms of Service for full details.