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

TIDE TIMES for Friday, July 31, 2026
The tide is currently rising in Roche Harbor, San Juan Island, WA.
Next low tide (tomorrow) : 1:32 am (5.0 ft)
Next high tide : in 3h 41m at 8:05 pm (7.7 ft)
Sunset today : 8:51 pm
Sunrise tomorrow : 5:46 am
Moon phase : Waning Gibbous (95% illuminated)
Tide Station Location : Station #9449834
Common Questions About Tides

Roche Harbor, San Juan Island, WA Tides - Jul 2086

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Mon8:005.89:508.23:074.52:29-0.25:159:18Waning Gibbous1Mon
2Tue9:165.210:248.24:083.43:151.15:159:18Third Quarter2Tue
3Wed10:474.810:598.15:092.34:032.55:169:17Third Quarter3Wed
4Thu12:464.86:081.14:594.05:179:17Third Quarter4Thu
5Fri2:445.47:040.06:075.25:189:16Waning Crescent5Fri
6Sat12:157.94:036.37:57-0.97:276.15:189:16Waning Crescent6Sat
7Sun12:587.74:597.08:47-1.68:436.55:199:15Waning Crescent7Sun
8Mon1:457.65:447.59:33-2.09:496.65:209:15Waning Crescent8Mon
9Tue2:367.46:247.810:16-2.110:466.45:219:14New Moon9Tue
10Wed3:297.27:007.910:58-2.011:376.25:229:14New Moon10Wed
11Thu4:217.07:338.011:38-1.75:239:13New Moon11Thu
12Fri5:126.78:047.912:275.812:18-1.35:249:12New Moon12Fri
13Sat6:036.38:317.81:175.412:57-0.65:259:11Waxing Crescent13Sat
14Sun6:555.98:567.72:074.81:360.25:269:11Waxing Crescent14Sun
15Mon7:495.59:197.62:584.22:141.15:279:10Waxing Crescent15Mon
16Tue8:505.19:437.53:483.62:532.25:289:09Waxing Crescent16Tue
17Wed10:034.710:117.44:382.93:323.35:299:08First Quarter17Wed
18Thu11:524.610:417.35:272.24:144.45:309:07First Quarter18Thu
19Fri2:295.06:161.65:075.35:319:06First Quarter19Fri
20Sat3:565.77:040.96:266.15:339:05First Quarter20Sat
21Sun4:426.37:500.37:476.55:349:04Waxing Gibbous21Sun
22Mon12:347.05:156.88:34-0.48:516.75:359:03Waxing Gibbous22Mon
23Tue1:217.15:437.19:17-1.09:416.65:369:01Waxing Gibbous23Tue
24Wed2:137.26:097.49:57-1.510:236.45:379:00Full Moon24Wed
25Thu3:087.26:347.610:38-1.811:066.05:398:59Full Moon25Thu
26Fri4:057.27:007.811:19-1.911:515.35:408:58Full Moon26Fri
27Sat5:047.17:277.912:00-1.65:418:56Full Moon27Sat
28Sun6:046.87:568.012:404.512:42-1.05:438:55Waning Gibbous28Sun
29Mon7:076.48:278.11:333.61:240.05:448:54Waning Gibbous29Mon
30Tue8:146.08:598.12:292.62:081.25:458:52Waning Gibbous30Tue
31Wed9:315.59:348.03:261.72:552.65:468:51Third Quarter31Wed
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 10:48 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 spring phase. Tonight's moon is 95% 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 Waning Gibbous (95% 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