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

TIDE TIMES for Thursday, July 30, 2026
The tide is currently falling in Roche Harbor, San Juan Island, WA.
Next low tide : in 5h 21m at 12:01 pm (-1.0 ft)
Next high tide : 7:46 pm (7.7 ft)
Sunset today : 8:53 pm
Sunrise tomorrow : 5:44 am
Moon phase : Full Moon (99% illuminated)
Tide Station Location : Station #9449834
Common Questions About Tides

Roche Harbor, San Juan Island, WA Tides - Apr 1978

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Sat12:207.010:03 AM6.35:195.75:160.15:506:42Third Quarter1Sat
2Sun1:227.211:24 AM6.06:445.26:230.45:486:44Waning Crescent2Sun
3Mon2:107.412:516.07:484.57:250.85:466:45Waning Crescent3Mon
4Tue2:517.52:136.28:363.68:191.25:436:47Waning Crescent4Tue
5Wed3:267.63:236.59:162.79:081.75:416:48New Moon5Wed
6Thu3:567.64:226.79:541.89:532.35:396:50New Moon6Thu
7Fri4:247.65:166.910:311.110:372.95:376:51New Moon7Fri
8Sat4:517.56:067.111:080.511:213.65:356:53New Moon8Sat
9Sun5:187.36:567.111:460.15:336:54Waxing Crescent9Sun
10Mon5:467.17:467.112:074.312:250.05:316:56Waxing Crescent10Mon
11Tue6:176.88:407.012:574.81:060.05:296:57Waxing Crescent11Tue
12Wed6:526.59:396.91:545.31:500.25:276:59Waxing Crescent12Wed
13Thu7:306.210:456.92:595.62:370.65:257:00First Quarter13Thu
14Fri8:155.811:506.84:195.73:301.05:237:02First Quarter14Fri
15Sat9:135.55:535.54:281.45:217:03First Quarter15Sat
16Sun12:446.910:24 AM5.27:085.25:291.75:197:04First Quarter16Sun
17Mon1:256.911:43 AM5.17:484.66:282.05:177:06Waxing Gibbous17Mon
18Tue1:556.91:045.38:134.07:212.25:157:07Waxing Gibbous18Tue
19Wed2:197.02:155.68:363.38:082.55:147:09Waxing Gibbous19Wed
20Thu2:437.13:156.09:012.48:512.85:127:10Waxing Gibbous20Thu
21Fri3:087.24:086.59:301.49:323.25:107:12Full Moon21Fri
22Sat3:377.44:596.910:030.410:133.75:087:13Full Moon22Sat
23Sun4:087.45:497.210:40-0.510:574.25:067:15Full Moon23Sun
24Mon4:427.46:417.511:20-1.211:444.75:047:16Full Moon24Mon
25Tue5:197.47:367.612:04-1.65:027:18Waning Gibbous25Tue
26Wed5:587.28:347.612:365.212:52-1.75:017:19Waning Gibbous26Wed
27Thu6:436.99:367.61:375.51:43-1.54:597:21Waning Gibbous27Thu
28Fri7:356.410:397.62:485.62:39-1.04:577:22Third Quarter28Fri
29Sat8:395.911:407.64:135.43:39-0.34:557:24Third Quarter29Sat
30Sun10:595.46:434.95:430.55:548:25Third Quarter30Sun
DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
Tidal Data Source: (9449834)

Common Questions About Roche Harbor, San Juan Island, WA Tides

Show All
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 3:53 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 99% 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 Full Moon (99% 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