Tides Today & Tomorrow in Boston, MA

TIDE TIMES for Tuesday, August 18, 2026
The tide is currently falling in Boston, MA.
Next low tide : in 6h 02m at 9:59 am (1.0 ft)
Next high tide : 4:15 pm (9.9 ft)
Sunset today : 7:40 pm
Sunrise tomorrow : 5:54 am
Moon phase : First Quarter (36% illuminated)
Tide Station Location : Station #8443970
Common Questions About Tides

Boston, MA Tides - Oct 1934

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Mon5:218.25:339.111:132.35:405:27Third Quarter1Mon
2Tue6:208.16:329.012:021.612:122.35:415:25Waning Crescent2Tue
3Wed7:158.37:289.112:581.61:092.15:425:23Waning Crescent3Wed
4Thu8:058.78:199.31:491.52:021.85:435:21Waning Crescent4Thu
5Fri8:499.19:049.52:341.22:491.45:445:20Waning Crescent5Fri
6Sat9:289.59:459.63:141.03:321.05:455:18New Moon6Sat
7Sun10:039.810:249.73:520.84:130.65:475:16New Moon7Sun
8Mon10:3810.111:029.84:290.74:520.35:485:15New Moon8Mon
9Tue11:1410.411:429.75:060.65:320.05:495:13New Moon9Tue
10Wed11:5110.55:440.66:13-0.15:505:11Waxing Crescent10Wed
11Thu12:239.612:3110.66:240.76:56-0.15:515:09Waxing Crescent11Thu
12Fri1:069.41:1410.67:060.97:420.05:525:08Waxing Crescent12Fri
13Sat1:529.22:0110.57:531.18:330.25:535:06Waxing Crescent13Sat
14Sun2:448.92:5510.48:451.39:290.45:555:05First Quarter14Sun
15Mon3:428.83:5510.29:431.410:300.55:565:03First Quarter15Mon
16Tue4:458.85:0010.010:471.411:320.55:575:01First Quarter16Tue
17Wed5:499.06:0710.011:531.25:585:00Waxing Gibbous17Wed
18Thu6:529.47:1310.112:330.412:580.95:594:58Waxing Gibbous18Thu
19Fri7:5210.08:1610.31:330.22:000.36:004:57Waxing Gibbous19Fri
20Sat8:4610.69:1310.52:290.02:58-0.26:024:55Waxing Gibbous20Sat
21Sun9:3611.010:0510.53:21-0.23:51-0.76:034:54Full Moon21Sun
22Mon10:2211.310:5410.44:09-0.24:41-0.96:044:52Full Moon22Mon
23Tue11:0711.311:4310.24:55-0.15:29-0.96:054:51Full Moon23Tue
24Wed11:5211.15:400.26:16-0.76:064:49Waning Gibbous24Wed
25Thu12:309.812:3710.86:260.67:02-0.36:084:48Waning Gibbous25Thu
26Fri1:179.41:2310.47:111.07:490.16:094:46Waning Gibbous26Fri
27Sat2:059.02:1010.07:571.58:380.76:104:45Waning Gibbous27Sat
28Sun2:548.63:009.58:471.99:291.16:114:43Third Quarter28Sun
29Mon3:478.43:549.29:402.210:231.46:134:42Third Quarter29Mon
30Tue4:428.24:518.910:362.311:171.66:144:41Third Quarter30Tue
31Wed5:368.35:488.811:332.36:154:39Third Quarter31Wed
DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
Tidal Data Source: (8443970)

Common Questions About Boston, MA Tides

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What time does the tide turn (slack tide) in Boston, MA today?

Slack tide in Boston, MA is approximately 1:07 pm — 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 Boston, MA?

Boston, MA is currently in a transitional phase. Tonight's moon is 36% 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 Boston, MA 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 Boston, MA?

Tide predictions for Boston, MA 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 Boston, MA?

Tide data for Boston, MA is sourced from NOAA Station #8443970. View the official NOAA station page at https://tidesandcurrents.noaa.gov/stationhome.html?id=8443970.

What is the moon phase in Boston, MA tonight?

Tonight the moon over Boston, MA is First Quarter (36% illuminated). This places Boston, MA 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