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 1h 34m 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 - Sep 2086

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Sun2:146.75:51-0.36:406.16:317:53Third Quarter1Sun
2Mon3:147.07:00-0.18:205.96:327:51Waning Crescent2Mon
3Tue12:316.34:017.28:040.09:265.46:337:49Waning Crescent3Tue
4Wed1:496.24:397.38:590.210:064.96:357:47Waning Crescent4Wed
5Thu3:016.25:107.39:450.510:374.36:367:45Waning Crescent5Thu
6Fri4:016.35:367.310:240.911:053.76:387:43New Moon6Fri
7Sat4:536.45:557.211:001.311:343.06:397:41New Moon7Sat
8Sun5:396.46:117.111:351.96:407:39New Moon8Sun
9Mon6:246.56:287.112:042.412:102.56:427:37New Moon9Mon
10Tue7:086.56:497.012:371.812:463.26:437:35Waxing Crescent10Tue
11Wed7:556.47:156.91:111.41:243.96:457:32Waxing Crescent11Wed
12Thu8:466.37:446.81:481.02:044.66:467:30Waxing Crescent12Thu
13Fri9:446.28:156.62:280.82:495.26:477:28Waxing Crescent13Fri
14Sat10:586.28:506.43:130.73:445.86:497:26First Quarter14Sat
15Sun12:326.24:040.64:566.26:507:24First Quarter15Sun
16Mon1:516.45:020.66:256.36:527:22First Quarter16Mon
17Tue2:426.76:050.57:376.06:537:20First Quarter17Tue
18Wed3:176.97:080.48:255.56:547:18Waxing Gibbous18Wed
19Thu12:556.13:457.18:060.49:044.76:567:16Waxing Gibbous19Thu
20Fri2:106.34:107.28:580.49:423.66:577:13Waxing Gibbous20Fri
21Sat3:226.64:357.49:450.710:222.46:597:11Full Moon21Sat
22Sun4:296.95:037.610:291.311:031.17:007:09Full Moon22Sun
23Mon5:327.25:327.711:142.111:460.07:017:07Full Moon23Mon
24Tue6:347.46:047.811:593.07:037:05Waning Gibbous24Tue
25Wed7:367.46:397.812:32-0.912:473.97:047:03Waning Gibbous25Wed
26Thu8:407.47:177.61:20-1.31:404.87:067:01Waning Gibbous26Thu
27Fri9:507.37:597.22:12-1.42:405.57:076:59Waning Gibbous27Fri
28Sat11:077.28:476.73:06-1.13:565.97:096:57Third Quarter28Sat
29Sun12:247.24:06-0.65:346.07:106:54Third Quarter29Sun
30Mon1:317.35:110.17:325.67:116:52Third Quarter30Mon
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 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