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

TIDE TIMES for Sunday, July 19, 2026
The tide is currently rising in Roche Harbor, San Juan Island, WA.
Next low tide (tomorrow) : 4:51 am (2.5 ft)
Next high tide : in 4h 16m at 9:59 pm (7.9 ft)
Sunset today : 9:06 pm
Sunrise tomorrow : 5:31 am
Moon phase : First Quarter (33% illuminated)
Tide Station Location : Station #9449834
Common Questions About Tides

Roche Harbor, San Juan Island, WA Tides - Oct 1989

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Sun7:046.75:547.012:031.012:154.37:126:51New Moon1Sun
2Mon7:506.86:156.912:330.412:545.07:146:49Waxing Crescent2Mon
3Tue8:396.96:386.71:050.01:375.77:156:47Waxing Crescent3Tue
4Wed9:356.96:596.51:41-0.22:276.27:166:45Waxing Crescent4Wed
5Thu10:436.97:096.42:22-0.23:326.77:186:43Waxing Crescent5Thu
6Fri12:067.03:08-0.17:196:41First Quarter6Fri
7Sat1:207.14:020.17:216:39First Quarter7Sat
8Sun2:107.25:050.37:226:37First Quarter8Sun
9Mon2:447.36:120.58:525.87:246:35First Quarter9Mon
10Tue3:097.47:160.68:584.97:256:33Waxing Gibbous10Tue
11Wed1:245.73:307.58:130.99:243.77:276:31Waxing Gibbous11Wed
12Thu2:486.03:517.69:031.49:562.27:286:29Waxing Gibbous12Thu
13Fri4:046.54:137.79:492.210:330.77:306:27Full Moon13Fri
14Sat5:137.04:387.910:343.211:12-0.87:316:25Full Moon14Sat
15Sun6:177.55:057.911:204.211:53-1.97:336:23Full Moon15Sun
16Mon7:187.85:357.912:075.27:346:21Waning Gibbous16Mon
17Tue8:218.06:087.712:38-2.51:006.17:366:19Waning Gibbous17Tue
18Wed9:268.06:447.41:25-2.62:016.77:376:17Waning Gibbous18Wed
19Thu10:368.07:256.92:16-2.23:207.07:396:15Third Quarter19Thu
20Fri11:477.98:186.33:11-1.55:296.87:406:13Third Quarter20Fri
21Sat12:517.94:12-0.67:496.17:426:12Third Quarter21Sat
22Sun1:447.85:190.38:405.37:436:10Third Quarter22Sun
23Mon2:277.86:281.29:144.47:456:08Waning Crescent23Mon
24Tue1:195.13:017.67:332.09:403.57:476:06Waning Crescent24Tue
25Wed2:575.43:267.58:292.710:012.67:486:04Waning Crescent25Wed
26Thu4:095.83:427.49:163.510:191.77:506:03Waning Crescent26Thu
27Fri5:076.33:537.29:594.310:400.87:516:01New Moon27Fri
28Sat5:566.84:057.210:385.011:030.17:535:59New Moon28Sat
29Sun5:417.23:237.110:185.610:29-0.56:544:57New Moon29Sun
30Mon6:227.53:447.110:596.210:58-0.96:564:56New Moon30Mon
31Tue7:037.74:076.911:446.611:31-1.16:574:54Waxing Crescent31Tue
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 1:25 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 Roche Harbor, San Juan Island, WA?

Roche Harbor, San Juan Island, WA is currently in a transitional phase. Tonight's moon is 33% 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 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 (33% illuminated). This places Roche Harbor, San Juan Island, WA 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