Tides Today & Tomorrow in Portsmouth, NH

TIDE TIMES for Saturday, July 18, 2026
The tide is currently falling in Portsmouth, NH.
Next low tide : in 5h 48m at 9:26 pm (0.1 ft)
Next high tide (tomorrow) : 3:44 am (8.7 ft)
Sunset today : 8:18 pm
Sunrise tomorrow : 5:20 am
Moon phase : Waxing Crescent (23% illuminated)
Tide Station Location : Station #8423745
Common Questions About Tides

Portsmouth, NH Tides - Oct 2066

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Fri10:148.610:368.93:54-0.24:16-0.26:406:24Waxing Gibbous1Fri
2Sat11:038.911:278.94:44-0.35:08-0.56:426:22Full Moon2Sat
3Sun11:489.15:30-0.35:57-0.66:436:20Full Moon3Sun
4Mon12:168.812:329.16:14-0.26:43-0.66:446:18Full Moon4Mon
5Tue1:028.61:139.06:560.17:27-0.56:456:17Waning Gibbous5Tue
6Wed1:468.31:548.87:370.48:10-0.26:466:15Waning Gibbous6Wed
7Thu2:297.92:368.58:180.78:540.26:476:13Waning Gibbous7Thu
8Fri3:147.53:208.19:011.19:410.56:486:11Waning Gibbous8Fri
9Sat4:027.24:087.89:481.410:310.96:506:10Third Quarter9Sat
10Sun4:556.95:027.610:391.711:251.16:516:08Third Quarter10Sun
11Mon5:506.85:597.411:351.86:526:06Third Quarter11Mon
12Tue6:456.76:567.312:211.312:321.86:536:05Third Quarter12Tue
13Wed7:406.97:537.41:161.31:311.76:546:03Waning Crescent13Wed
14Thu8:327.28:477.62:091.12:271.46:566:01Waning Crescent14Thu
15Fri9:177.59:357.82:560.93:171.06:576:00Waning Crescent15Fri
16Sat9:588.010:198.03:380.74:010.56:585:58Waning Crescent16Sat
17Sun10:368.411:018.24:180.44:430.16:595:56New Moon17Sun
18Mon11:148.811:438.44:560.25:24-0.47:005:55New Moon18Mon
19Tue11:549.25:360.16:07-0.77:025:53New Moon19Tue
20Wed12:278.512:359.46:180.06:52-0.97:035:52New Moon20Wed
21Thu1:128.51:209.57:030.07:39-0.97:045:50Waxing Crescent21Thu
22Fri1:598.32:089.47:500.18:29-0.87:055:49Waxing Crescent22Fri
23Sat2:508.23:009.28:410.29:24-0.57:065:47Waxing Crescent23Sat
24Sun3:477.93:599.09:380.510:24-0.37:085:46First Quarter24Sun
25Mon4:507.85:058.710:410.711:280.07:095:44First Quarter25Mon
26Tue5:567.76:138.411:480.87:105:43First Quarter26Tue
27Wed7:017.97:228.312:330.112:580.77:115:41Waxing Gibbous27Wed
28Thu8:058.18:298.31:380.22:080.57:135:40Waxing Gibbous28Thu
29Fri9:038.49:298.32:390.23:110.27:145:38Waxing Gibbous29Fri
30Sat9:558.710:238.43:340.14:06-0.27:155:37Waxing Gibbous30Sat
31Sun10:428.911:138.34:230.14:56-0.47:175:36Full Moon31Sun
DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
Tidal Data Source: (8423745)

Common Questions About Portsmouth, NH Tides

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What time does the tide turn (slack tide) in Portsmouth, NH today?

Slack tide in Portsmouth, NH is approximately 12:35 am — midway between the next high and low tide, when tidal current is weakest. This is the preferred window for boat crossings, underwater visibility, and fishing in areas with strong currents.

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

Portsmouth, NH is currently in a transitional phase. Tonight's moon is 23% 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 shifting between spring and neap.

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 Waxing Crescent (23% illuminated). This places Portsmouth, NH in a transitional tide cycle, so tidal ranges are shifting between spring and neap 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