Nearby Harbors
43.0783’ N, 70.7517’ W

Portsmouth, NH

69°
H -°
L 46°
NW
9mph
Low tide
11:55 pm
Photo Credits

Tides Today & Tomorrow in Portsmouth, NH

TIDE TIMES for Friday, September 18, 2026
The tide is currently falling in Portsmouth, NH.
Next low tide : in 4h 48m at 11:55 pm (1.3 ft)
Next high tide (tomorrow) : 6:18 am (6.5 ft)
Sunset today : 6:47 pm
Sunrise tomorrow : 6:26 am
Moon phase : First Quarter (48% illuminated)
Tide Station Location : Station #8423745
Common Questions About Tides

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Portsmouth, NH Tides - Mar 1902

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Common Questions About Portsmouth, NH Tides

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Is this week a spring tide or neap tide in Portsmouth, NH?

Portsmouth, NH is currently in a neap phase. Tonight's moon is 48% illuminated. Spring tides (largest swings) occur near new and full moons; neap tides (smallest swings) occur near first and third quarter moons. Tidal ranges this week are near their weekly minimum.

What datum are Portsmouth, NH tide heights measured from?

Tide heights on this page are measured from Mean Lower Low Water (MLLW), the U.S. NOAA standard. A height of 0 ft represents the 19-year average of each day's lower low tide. Negative values indicate a "minus tide" — water levels below that long-term reference.

What factors can affect the tide predictions for Portsmouth, NH?

Tide predictions for Portsmouth, NH come from NOAA's harmonic analysis and are typically accurate within about ±10 minutes on timing and ±0.5 ft on height. Actual water levels can deviate further due to sustained winds, atmospheric pressure changes, river flow, and storm surge. During major weather events, be sure to check US Harbors weather pages for factors that could impact tidal predictions.

Which NOAA station provides tide data for Portsmouth, NH?

Tide data for Portsmouth, NH is sourced from NOAA Station #8423745. View the official NOAA station page at https://tidesandcurrents.noaa.gov/stationhome.html?id=8423745.

What is the moon phase in Portsmouth, NH tonight?

Tonight the moon over Portsmouth, NH is First Quarter (48% illuminated). This places Portsmouth, NH in a neap tide cycle, so tidal ranges are near their weekly minimum this week.

US Harbors Tidal Data

The data in our tide charts, tide tables, and tide graphs is provided by NOAA and others. These predictions are derived mathematically from numerous inputs, including data from historical tide stations and nearby locations where sensors are actively recording. As shown in the tide graph at the top of this page, “Predicted” tides (blue) are what forecasting models expect to happen. “Observed” tides (red) are those recorded by local sensors in real time, overlaid on the predictions for direct comparison. We display Observed water levels for a select group of harbors including Portland, Maine, where a physical sensor monitors water levels in real time.

LEARN MORE ABOUT OUR TIDE DATA

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