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

TIDE TIMES for Saturday, July 18, 2026
The tide is currently rising in Roche Harbor, San Juan Island, WA.
Next low tide (tomorrow) : 3:52 am (3.5 ft)
Next high tide : in 5h 10m at 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 - Apr 2071

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Wed5:587.46:517.012:100.96:497:43New Moon1Wed
2Thu6:287.47:437.112:203.212:490.26:477:44Waxing Crescent2Thu
3Fri7:017.48:397.11:033.91:32-0.46:457:46Waxing Crescent3Fri
4Sat7:367.39:417.01:504.52:20-0.76:427:47Waxing Crescent4Sat
5Sun8:157.010:517.02:435.13:12-0.76:407:49Waxing Crescent5Sun
6Mon9:016.73:485.54:09-0.56:387:50First Quarter6Mon
7Tue12:077.09:59 AM6.35:085.75:12-0.26:367:52First Quarter7Tue
8Wed1:187.111:14 AM6.06:385.56:190.26:347:53First Quarter8Wed
9Thu2:167.312:415.77:594.87:260.76:327:55Waxing Gibbous9Thu
10Fri3:027.42:135.88:564.08:271.16:307:56Waxing Gibbous10Fri
11Sat3:417.53:346.19:403.09:211.66:287:58Waxing Gibbous11Sat
12Sun4:157.64:416.410:182.110:102.26:267:59Full Moon12Sun
13Mon4:457.65:386.810:541.210:562.86:248:01Full Moon13Mon
14Tue5:137.56:307.011:300.511:403.56:228:02Full Moon14Tue
15Wed5:407.47:207.212:070.06:208:04Full Moon15Wed
16Thu6:087.28:097.312:264.112:44-0.36:188:05Waning Gibbous16Thu
17Fri6:387.08:587.21:144.71:23-0.36:178:07Waning Gibbous17Fri
18Sat7:116.79:517.22:075.12:04-0.26:158:08Waning Gibbous18Sat
19Sun7:476.410:487.13:075.52:480.16:138:10Waning Gibbous19Sun
20Mon8:286.011:497.04:175.73:350.56:118:11Third Quarter20Mon
21Tue9:175.65:395.64:271.06:098:13Third Quarter21Tue
22Wed12:477.010:18 AM5.37:065.35:241.56:078:14Third Quarter22Wed
23Thu1:357.011:32 AM5.08:084.86:251.96:058:16Third Quarter23Thu
24Fri2:137.012:545.08:434.37:242.36:038:17Waning Crescent24Fri
25Sat2:417.02:175.29:093.68:182.66:028:18Waning Crescent25Sat
26Sun3:067.13:295.69:332.79:052.96:008:20Waning Crescent26Sun
27Mon3:317.24:286.110:001.89:493.35:588:21Waning Crescent27Mon
28Tue3:597.35:206.510:300.810:313.75:568:23New Moon28Tue
29Wed4:297.46:107.011:04-0.211:134.25:558:24New Moon29Wed
30Thu5:017.46:597.411:41-1.111:584.75:538:26New Moon30Thu
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 12:41 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 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