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

TIDE TIMES for Saturday, July 18, 2026
The tide is currently falling in Roche Harbor, San Juan Island, WA.
Next low tide : in 6h 05m at 2:15 pm (0.0 ft)
Next high tide : 9:31 pm (8.1 ft)
Sunset today : 9:07 pm
Sunrise tomorrow : 5:30 am
Moon phase : Waxing Crescent (24% illuminated)
Tide Station Location : Station #9449834
Common Questions About Tides

Roche Harbor, San Juan Island, WA Tides - Jan 2071

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Thu6:168.23:277.211:006.710:43-0.78:044:27New Moon1Thu
2Fri6:448.34:097.011:416.511:17-0.68:044:28New Moon2Fri
3Sat7:098.34:526.812:246.38:044:29Waxing Crescent3Sat
4Sun7:358.35:376.51:106.08:044:31Waxing Crescent4Sun
5Mon8:028.46:266.112:270.11:585.58:044:32Waxing Crescent5Mon
6Tue8:318.47:225.71:040.72:474.98:034:33Waxing Crescent6Tue
7Wed9:028.38:285.21:421.43:374.28:034:34First Quarter7Wed
8Thu9:358.39:495.02:212.34:273.38:034:35First Quarter8Thu
9Fri10:108.211:345.03:063.45:182.38:024:36First Quarter9Fri
10Sat10:478.14:014.56:091.28:024:38First Quarter10Sat
11Sun1:395.611:27 AM8.15:125.46:580.18:014:39Waxing Gibbous11Sun
12Mon2:586.412:118.16:306.17:46-0.98:014:40Waxing Gibbous12Mon
13Tue3:507.21:008.27:426.58:33-1.78:004:42Waxing Gibbous13Tue
14Wed4:347.81:548.28:456.59:19-2.27:594:43Full Moon14Wed
15Thu5:138.32:518.19:426.410:05-2.47:594:44Full Moon15Thu
16Fri5:528.63:497.910:376.010:51-2.27:584:46Full Moon16Fri
17Sat6:298.84:477.511:335.511:36-1.67:574:47Waning Gibbous17Sat
18Sun7:068.95:467.112:325.07:564:49Waning Gibbous18Sun
19Mon7:438.86:486.512:22-0.71:334.37:554:50Waning Gibbous19Mon
20Tue8:208.77:555.91:080.52:353.77:544:52Waning Gibbous20Tue
21Wed8:568.59:195.41:551.73:393.07:544:53Third Quarter21Wed
22Thu9:328.311:155.22:443.14:412.47:534:55Third Quarter22Thu
23Fri10:088.03:394.35:421.87:514:56Third Quarter23Fri
24Sat1:105.610:46 AM7.74:475.46:371.37:504:58Third Quarter24Sat
25Sun2:326.311:27 AM7.46:086.27:250.87:495:00Waning Crescent25Sun
26Mon3:296.912:117.27:306.58:070.57:485:01Waning Crescent26Mon
27Tue4:127.412:597.18:376.68:440.27:475:03Waning Crescent27Tue
28Wed4:487.71:477.19:256.59:180.07:465:04Waning Crescent28Wed
29Thu5:187.92:347.110:036.39:51-0.17:445:06New Moon29Thu
30Fri5:437.93:207.010:376.110:24-0.17:435:08New Moon30Fri
31Sat6:068.04:057.011:115.710:570.07:425:09New Moon31Sat
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 5:53 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 transitional phase. Tonight's moon is 24% 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 Waxing Crescent (24% 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