Tides Today & Tomorrow in Boston, MA

TIDE TIMES for Tuesday, July 21, 2026
The tide is currently falling in Boston, MA.
Next low tide (tomorrow) : in 1h 20m at 12:07 am (1.1 ft)
Next high tide (tomorrow) : 6:21 am (8.7 ft)
Sunset today : 8:14 pm
Sunrise tomorrow : 5:26 am
Moon phase : First Quarter (52% illuminated)
Tide Station Location : Station #8443970
Common Questions About Tides

Boston, MA Tides - Apr 1979

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Sun1:5610.82:309.98:14-0.78:310.35:266:08Waxing Crescent1Sun
2Mon2:4510.33:239.39:06-0.19:230.95:256:10First Quarter2Mon
3Tue3:379.74:198.810:010.510:181.45:236:11First Quarter3Tue
4Wed4:349.35:178.510:581.011:151.85:216:12First Quarter4Wed
5Thu5:329.06:168.311:561.25:206:13First Quarter5Thu
6Fri6:328.97:138.412:131.912:531.35:186:14Waxing Gibbous6Fri
7Sat7:308.98:068.71:101.81:471.35:166:15Waxing Gibbous7Sat
8Sun8:239.18:529.02:051.52:361.15:146:16Waxing Gibbous8Sun
9Mon9:099.39:339.42:531.13:190.85:136:17Waxing Gibbous9Mon
10Tue9:519.610:119.73:370.73:580.65:116:19Full Moon10Tue
11Wed10:319.710:4710.04:180.44:360.45:096:20Full Moon11Wed
12Thu11:099.811:2310.24:570.15:140.35:086:21Full Moon12Thu
13Fri11:489.95:37-0.25:520.25:066:22Full Moon13Fri
14Sat12:0010.412:289.86:17-0.36:320.35:056:23Waning Gibbous14Sat
15Sun12:3910.51:109.76:59-0.47:140.45:036:24Waning Gibbous15Sun
16Mon1:2010.51:549.67:43-0.47:580.55:016:25Waning Gibbous16Mon
17Tue2:0510.52:429.48:31-0.28:480.75:006:26Waning Gibbous17Tue
18Wed2:5510.43:369.39:24-0.19:430.84:586:28Third Quarter18Wed
19Thu3:5110.24:359.310:210.110:430.94:576:29Third Quarter19Thu
20Fri4:5210.15:379.411:210.111:450.84:556:30Third Quarter20Fri
21Sat5:5610.16:409.612:220.04:536:31Waning Crescent21Sat
22Sun7:0210.27:4110.112:490.51:23-0.14:526:32Waning Crescent22Sun
23Mon8:0610.48:3910.61:520.02:22-0.44:506:33Waning Crescent23Mon
24Tue9:0510.79:3211.02:51-0.53:16-0.64:496:34Waning Crescent24Tue
25Wed10:0010.810:2111.33:46-0.94:07-0.74:476:35New Moon25Wed
26Thu10:5110.911:0911.44:37-1.24:56-0.74:466:37New Moon26Thu
27Fri11:4210.711:5611.35:27-1.35:43-0.44:456:38New Moon27Fri
28Sat12:3010.46:15-1.26:30-0.14:436:39Waxing Crescent28Sat
29Sun12:4211.12:1810.18:02-0.88:160.35:427:40Waxing Crescent29Sun
30Mon2:2810.73:069.78:49-0.49:030.85:407:41Waxing Crescent30Mon
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 3:14 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 Boston, MA?

Boston, MA is currently in a neap phase. Tonight's moon is 52% 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 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 (52% illuminated). This places Boston, MA 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