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

TIDE TIMES for Monday, July 20, 2026
The tide is currently falling in Roche Harbor, San Juan Island, WA.
Next low tide : in 4h 01m at 3:43 pm (3.1 ft)
Next high tide : 10:25 pm (7.7 ft)
Sunset today : 9:05 pm
Sunrise tomorrow : 5:32 am
Moon phase : First Quarter (43% illuminated)
Tide Station Location : Station #9449834
Common Questions About Tides

Roche Harbor, San Juan Island, WA Tides - Aug 2071

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Sat9:535.410:077.83:582.33:282.45:478:50First Quarter1Sat
2Sun11:335.210:467.55:001.74:243.65:498:48First Quarter2Sun
3Mon1:235.46:031.25:314.75:508:47First Quarter3Mon
4Tue2:515.97:030.86:495.45:518:45First Quarter4Tue
5Wed12:126.93:566.57:580.58:105.85:538:44Waxing Gibbous5Wed
6Thu1:006.74:456.98:460.29:185.85:548:42Waxing Gibbous6Thu
7Fri1:506.65:247.29:270.010:075.85:558:41Waxing Gibbous7Fri
8Sat2:406.65:577.310:04-0.110:455.65:578:39Waxing Gibbous8Sat
9Sun3:276.66:257.310:39-0.211:185.35:588:37Full Moon9Sun
10Mon4:136.66:487.311:12-0.111:515.05:598:36Full Moon10Mon
11Tue4:586.57:087.411:460.06:018:34Full Moon11Tue
12Wed5:426.57:297.412:264.612:190.36:028:32Full Moon12Wed
13Thu6:296.37:527.41:024.112:530.86:048:30Waning Gibbous13Thu
14Fri7:176.18:207.41:423.61:291.46:058:29Waning Gibbous14Fri
15Sat8:105.88:507.42:243.02:062.16:068:27Waning Gibbous15Sat
16Sun9:095.69:237.33:092.42:452.96:088:25Waning Gibbous16Sun
17Mon10:195.49:587.23:581.83:293.86:098:23Third Quarter17Mon
18Tue11:485.310:387.14:521.14:244.76:118:21Third Quarter18Tue
19Wed1:365.65:500.55:355.36:128:20Third Quarter19Wed
20Thu2:586.16:50-0.16:565.76:138:18Waning Crescent20Thu
21Fri12:197.13:536.77:49-0.78:105.76:158:16Waning Crescent21Fri
22Sat1:217.14:357.18:44-1.19:105.36:168:14Waning Crescent22Sat
23Sun2:277.25:127.49:35-1.310:034.86:188:12New Moon23Sun
24Mon3:327.25:477.610:24-1.310:524.06:198:10New Moon24Mon
25Tue4:357.36:207.811:10-1.011:413.36:208:08New Moon25Tue
26Wed5:367.26:537.811:55-0.36:228:06New Moon26Wed
27Thu6:357.07:267.812:302.612:410.66:238:04Waxing Crescent27Thu
28Fri7:366.78:007.71:212.01:281.66:258:02Waxing Crescent28Fri
29Sat8:406.38:357.52:131.52:172.76:268:00Waxing Crescent29Sat
30Sun9:546.19:117.23:061.23:113.76:277:58First Quarter30Sun
31Mon11:225.99:516.84:021.04:134.66:297:56First Quarter31Mon
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 7:04 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 neap phase. Tonight's moon is 43% 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 minimum.

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 First Quarter (43% illuminated). This places Roche Harbor, San Juan Island, WA in a neap tide cycle, so tidal ranges are near their weekly minimum 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