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 2h 01m at 1:44 am (5.4 ft)
Next high tide : 6:35 am (6.6 ft)
Sunset today : 9:09 pm
Sunrise tomorrow : 5:27 am
Moon phase : Waxing Crescent (8% illuminated)
Tide Station Location : Station #9449834
Common Questions About Tides

Roche Harbor, San Juan Island, WA Tides - Sep 1990

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Sat1:086.25:067.28:590.110:055.86:297:55Waxing Gibbous1Sat
2Sun2:136.35:257.29:40-0.110:275.36:317:53Waxing Gibbous2Sun
3Mon3:146.55:417.310:17-0.110:544.56:327:51Full Moon3Mon
4Tue4:126.65:577.410:530.211:263.66:347:49Full Moon4Tue
5Wed5:096.76:167.511:280.76:357:47Full Moon5Wed
6Thu6:066.76:397.612:032.512:051.56:367:44Full Moon6Thu
7Fri7:066.77:047.612:431.412:432.56:387:42Waning Gibbous7Fri
8Sat8:106.67:317.61:260.41:253.76:397:40Waning Gibbous8Sat
9Sun9:216.58:017.52:14-0.42:104.86:417:38Waning Gibbous9Sun
10Mon10:476.48:357.33:06-0.93:025.76:427:36Third Quarter10Mon
11Tue12:296.64:03-1.14:126.56:437:34Third Quarter11Tue
12Wed1:576.95:07-1.05:536.86:457:32Third Quarter12Wed
13Thu2:587.26:17-0.87:486.56:467:30Waning Crescent13Thu
14Fri3:437.47:27-0.69:025.96:487:28Waning Crescent14Fri
15Sat1:056.34:197.58:30-0.39:455.16:497:26Waning Crescent15Sat
16Sun2:316.34:507.59:230.110:214.26:507:23Waning Crescent16Sun
17Mon3:456.45:167.510:080.610:543.36:527:21New Moon17Mon
18Tue4:496.55:377.410:481.311:272.36:537:19New Moon18Tue
19Wed5:466.65:557.311:272.26:557:17New Moon19Wed
20Thu6:406.76:137.212:011.512:053.16:567:15New Moon20Thu
21Fri7:336.76:327.112:350.812:464.06:577:13Waxing Crescent21Fri
22Sat8:276.76:556.91:100.31:304.86:597:11Waxing Crescent22Sat
23Sun9:266.77:206.71:480.12:205.67:007:09Waxing Crescent23Sun
24Mon10:376.77:486.42:290.13:226.17:027:06Waxing Crescent24Mon
25Tue12:026.73:140.24:486.57:037:04First Quarter25Tue
26Wed1:226.84:060.57:336.57:057:02First Quarter26Wed
27Thu2:226.95:070.88:526.27:067:00First Quarter27Thu
28Fri3:037.16:141.09:135.97:076:58First Quarter28Fri
29Sat3:327.17:181.09:215.47:096:56Waxing Gibbous29Sat
30Sun12:585.63:527.28:121.19:344.77:106:54Waxing Gibbous30Sun
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 8% 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 (8% 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