Tides Today & Tomorrow in Roche Harbor, San Juan Island, WA

TIDE TIMES for Tuesday, July 21, 2026
The tide is currently falling in Roche Harbor, San Juan Island, WA.
Next low tide : in 1h 52m at 4:34 pm (4.5 ft)
Next high tide : 10:51 pm (7.5 ft)
Sunset today : 9:04 pm
Sunrise tomorrow : 5:33 am
Moon phase : First Quarter (53% illuminated)
Tide Station Location : Station #9449834
Common Questions About Tides

Roche Harbor, San Juan Island, WA Tides - Jan 2072

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Fri2:375.712:077.96:045.67:380.48:044:27Waxing Gibbous1Fri
2Sat3:346.512:468.07:136.28:17-0.68:044:28Waxing Gibbous2Sat
3Sun4:187.21:288.08:146.58:57-1.58:044:29Waxing Gibbous3Sun
4Mon4:577.82:148.19:086.79:39-2.28:044:30Full Moon4Mon
5Tue5:358.33:048.110:016.610:23-2.58:044:31Full Moon5Tue
6Wed6:138.63:587.910:546.411:08-2.58:034:33Full Moon6Wed
7Thu6:528.84:547.611:506.111:54-2.08:034:34Waning Gibbous7Thu
8Fri7:318.95:547.112:515.68:034:35Waning Gibbous8Fri
9Sat8:118.96:586.512:41-1.21:574.98:024:36Waning Gibbous9Sat
10Sun8:518.98:115.81:29-0.13:064.18:024:37Third Quarter10Sun
11Mon9:318.79:425.22:191.24:153.28:014:39Third Quarter11Mon
12Tue10:118.511:445.23:122.75:232.38:014:40Third Quarter12Tue
13Wed10:528.34:114.06:231.48:004:41Third Quarter13Wed
14Thu1:355.711:33 AM8.05:225.27:150.77:594:43Waning Crescent14Thu
15Fri2:536.512:157.86:416.07:590.17:594:44Waning Crescent15Fri
16Sat3:507.212:577.67:576.58:38-0.27:584:46Waning Crescent16Sat
17Sun4:357.71:407.49:016.69:13-0.57:574:47Waning Crescent17Sun
18Mon5:148.12:237.29:526.69:47-0.67:564:48New Moon18Mon
19Tue5:488.23:067.110:346.510:21-0.57:564:50New Moon19Tue
20Wed6:188.23:497.011:146.310:55-0.47:554:51New Moon20Wed
21Thu6:448.24:336.811:536.011:29-0.17:544:53New Moon21Thu
22Fri7:088.25:176.612:345.67:534:54Waxing Crescent22Fri
23Sat7:318.26:046.312:040.31:175.27:524:56Waxing Crescent23Sat
24Sun7:558.26:545.912:390.92:024.77:514:58Waxing Crescent24Sun
25Mon8:228.17:515.51:141.62:484.17:504:59Waxing Crescent25Mon
26Tue8:528.08:585.21:502.43:353.57:485:01First Quarter26Tue
27Wed9:257.910:225.02:273.44:252.77:475:02First Quarter27Wed
28Thu9:597.83:104.45:161.97:465:04First Quarter28Thu
29Fri12:295.310:37 AM7.74:075.36:071.07:455:06First Quarter29Fri
30Sat2:195.911:19 AM7.75:286.16:580.17:435:07Waxing Gibbous30Sat
31Sun3:166.712:077.76:506.57:47-0.77:425:09Waxing Gibbous31Sun
DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
Tidal Data Source: (9449834)

Common Questions About Roche Harbor, San Juan Island, WA Tides

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What time does the tide turn (slack tide) in Roche Harbor, San Juan Island, WA today?

Slack tide in Roche Harbor, San Juan Island, WA is approximately 7:42 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 Roche Harbor, San Juan Island, WA?

Roche Harbor, San Juan Island, WA is currently in a neap phase. Tonight's moon is 53% 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 Roche Harbor, San Juan Island, WA 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 Roche Harbor, San Juan Island, WA?

Tide predictions for Roche Harbor, San Juan Island, WA 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 Roche Harbor, San Juan Island, WA?

Tide data for Roche Harbor, San Juan Island, WA is sourced from NOAA Station #9449834. View the official NOAA station page at https://tidesandcurrents.noaa.gov/stationhome.html?id=9449834.

What is the moon phase in Roche Harbor, San Juan Island, WA tonight?

Tonight the moon over Roche Harbor, San Juan Island, WA is First Quarter (53% illuminated). This places Roche Harbor, San Juan Island, WA 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