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 3h 20m at 2:49 am (4.5 ft)
Next high tide : 7:42 am (5.9 ft)
Sunset today : 9:08 pm
Sunrise tomorrow : 5:28 am
Moon phase : Waxing Crescent (15% illuminated)
Tide Station Location : Station #9449834
Common Questions About Tides

Roche Harbor, San Juan Island, WA Tides - Jul 2070

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Tue11:264.611:357.85:522.54:383.05:159:18Third Quarter1Tue
2Wed1:154.76:431.45:384.05:159:18Third Quarter2Wed
3Thu12:127.83:045.47:330.26:485.05:169:17Waning Crescent3Thu
4Fri12:537.84:156.28:21-0.98:005.65:179:17Waning Crescent4Fri
5Sat1:377.95:086.99:08-1.89:065.95:179:17Waning Crescent5Sat
6Sun2:267.95:537.59:55-2.510:066.05:189:16New Moon6Sun
7Mon3:197.86:357.910:41-2.811:035.85:199:16New Moon7Mon
8Tue4:157.67:158.111:27-2.85:209:15New Moon8Tue
9Wed5:127.37:548.212:005.512:13-2.45:219:14Waxing Crescent9Wed
10Thu6:106.98:328.212:595.112:59-1.75:229:14Waxing Crescent10Thu
11Fri7:096.39:098.22:024.61:46-0.75:239:13Waxing Crescent11Fri
12Sat8:125.79:458.03:064.02:320.45:249:12Waxing Crescent12Sat
13Sun9:235.210:207.94:113.33:201.75:259:11First Quarter13Sun
14Mon10:554.810:557.65:142.64:112.95:269:11First Quarter14Mon
15Tue12:574.86:131.95:084.15:279:10First Quarter15Tue
16Wed2:405.37:081.36:165.15:289:09First Quarter16Wed
17Thu12:067.23:536.07:570.87:325.75:299:08Waxing Gibbous17Thu
18Fri12:447.04:466.58:390.38:436.15:309:07Waxing Gibbous18Fri
19Sat1:266.95:266.99:17-0.19:406.25:319:06Waxing Gibbous19Sat
20Sun2:106.86:007.29:53-0.410:256.15:329:05Waxing Gibbous20Sun
21Mon2:556.86:297.310:27-0.611:046.05:349:04Full Moon21Mon
22Tue3:416.86:547.411:00-0.811:405.85:359:03Full Moon22Tue
23Wed4:276.77:177.511:34-0.85:369:01Full Moon23Wed
24Thu5:146.67:407.612:175.512:08-0.75:379:00Full Moon24Thu
25Fri6:016.48:057.712:565.012:44-0.45:398:59Waning Gibbous25Fri
26Sat6:526.28:337.81:394.51:210.15:408:58Waning Gibbous26Sat
27Sun7:475.89:037.82:253.81:590.95:418:56Waning Gibbous27Sun
28Mon8:485.59:367.83:153.12:401.85:428:55Waning Gibbous28Mon
29Tue10:005.110:117.74:072.23:242.85:448:54Third Quarter29Tue
30Wed11:305.010:497.65:021.44:153.95:458:52Third Quarter30Wed
31Thu1:245.36:000.55:194.95:468:51Third Quarter31Thu
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 5:15 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 spring phase. Tonight's moon is 15% 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 maximum.

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 (15% illuminated). This places Roche Harbor, San Juan Island, WA in a spring tide cycle, so tidal ranges are near their weekly maximum 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