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 1h 59m at 2:49 am (4.5 ft)
Next high tide : 7:42 am (5.9 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 - Aug 2070

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Fri3:005.96:58-0.36:375.65:488:49Waning Crescent1Fri
2Sat12:217.54:036.57:55-1.07:565.95:498:48Waning Crescent2Sat
3Sun1:167.54:507.08:49-1.59:035.85:508:46Waning Crescent3Sun
4Mon2:167.45:307.49:39-1.810:015.55:528:45New Moon4Mon
5Tue3:187.46:077.710:26-1.810:545.05:538:43New Moon5Tue
6Wed4:197.36:427.811:12-1.611:454.45:548:42New Moon6Wed
7Thu5:187.17:157.911:56-1.05:568:40New Moon7Thu
8Fri6:156.87:477.912:363.912:39-0.35:578:39Waxing Crescent8Fri
9Sat7:126.48:187.81:273.31:230.75:588:37Waxing Crescent9Sat
10Sun8:126.08:497.62:202.72:081.86:008:35Waxing Crescent10Sun
11Mon9:195.69:207.43:132.32:552.86:018:33Waxing Crescent11Mon
12Tue10:425.39:547.14:071.93:473.96:038:32First Quarter12Tue
13Wed12:315.45:021.64:474.86:048:30First Quarter13Wed
14Thu2:095.75:591.36:025.56:058:28First Quarter14Thu
15Fri3:196.26:571.17:245.86:078:26First Quarter15Fri
16Sat12:016.54:106.57:520.88:365.96:088:25Waxing Gibbous16Sat
17Sun12:556.44:476.88:400.69:285.76:098:23Waxing Gibbous17Sun
18Mon1:506.45:187.09:220.310:055.56:118:21Waxing Gibbous18Mon
19Tue2:446.55:427.110:000.110:375.16:128:19Waxing Gibbous19Tue
20Wed3:366.66:037.210:350.011:084.76:148:17Full Moon20Wed
21Thu4:256.76:237.311:090.111:414.16:158:15Full Moon21Thu
22Fri5:146.76:457.411:440.36:168:13Full Moon22Fri
23Sat6:046.67:117.512:183.512:200.76:188:11Waning Gibbous23Sat
24Sun6:576.57:407.512:582.812:581.46:198:09Waning Gibbous24Sun
25Mon7:536.38:127.51:422.01:392.26:218:08Waning Gibbous25Mon
26Tue8:556.18:477.52:301.32:223.16:228:06Waning Gibbous26Tue
27Wed10:075.99:257.33:220.73:124.06:238:04Third Quarter27Wed
28Thu11:365.810:097.24:190.34:114.96:258:02Third Quarter28Thu
29Fri1:176.05:200.05:265.56:268:00Third Quarter29Fri
30Sat2:356.56:26-0.36:525.76:287:58Waning Crescent30Sat
31Sun12:046.83:326.97:30-0.58:105.56:297:56Waning Crescent31Sun
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 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