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

TIDE TIMES for Friday, July 17, 2026
The tide is currently falling in Roche Harbor, San Juan Island, WA.
Next low tide : in 39m at 1:44 am (5.4 ft)
Next high tide : 6:35 am (6.6 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 - Aug 1990

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Wed4:577.08:010.19:006.95:468:50Waxing Gibbous1Wed
2Thu12:246.75:317.38:48-0.39:576.85:488:49Waxing Gibbous2Thu
3Fri1:186.66:007.49:31-0.610:316.75:498:47Waxing Gibbous3Fri
4Sat2:156.76:247.510:10-0.910:586.55:508:46Full Moon4Sat
5Sun3:106.86:467.510:46-1.111:286.15:528:44Full Moon5Sun
6Mon4:046.87:047.611:21-1.15:538:43Full Moon6Mon
7Tue4:566.77:237.712:015.511:56 AM-0.95:558:41Full Moon7Tue
8Wed5:516.57:447.812:394.812:31-0.35:568:40Waning Gibbous8Wed
9Thu6:496.38:077.81:213.91:080.55:578:38Waning Gibbous9Thu
10Fri7:515.98:327.82:072.81:451.65:598:36Waning Gibbous10Fri
11Sat9:025.69:007.82:551.82:242.96:008:34Waning Gibbous11Sat
12Sun10:275.49:297.73:470.83:074.26:018:33Third Quarter12Sun
13Mon12:245.54:42-0.13:565.46:038:31Third Quarter13Mon
14Tue2:256.15:42-0.75:086.46:048:29Third Quarter14Tue
15Wed3:396.76:45-1.26:486.96:068:27Waning Crescent15Wed
16Thu4:277.27:48-1.58:206.96:078:26Waning Crescent16Thu
17Fri12:467.15:057.58:47-1.79:286.56:088:24Waning Crescent17Fri
18Sat2:007.05:387.79:40-1.710:205.96:108:22New Moon18Sat
19Sun3:127.06:087.710:27-1.411:055.16:118:20New Moon19Sun
20Mon4:186.96:367.711:09-0.911:484.36:138:18New Moon20Mon
21Tue5:186.77:007.711:50-0.26:148:16New Moon21Tue
22Wed6:166.57:227.612:323.512:290.86:158:15Waxing Crescent22Wed
23Thu7:146.27:427.51:152.71:081.96:178:13Waxing Crescent23Thu
24Fri8:156.08:047.31:582.01:493.06:188:11Waxing Crescent24Fri
25Sat9:235.88:277.12:411.42:324.16:208:09Waxing Crescent25Sat
26Sun10:525.78:546.93:261.03:215.16:218:07First Quarter26Sun
27Mon12:475.94:140.84:266.06:228:05First Quarter27Mon
28Tue2:256.35:080.76:026.56:248:03First Quarter28Tue
29Wed3:286.76:080.78:026.66:258:01First Quarter29Wed
30Thu4:106.97:110.69:166.46:277:59Waxing Gibbous30Thu
31Fri4:427.18:090.39:456.26:287:57Waxing Gibbous31Fri
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 4:09 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