Tides Today & Tomorrow in Southwest Harbor, ME
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Southwest Harbor, ME Tides - May 2025
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Common Questions About Southwest Harbor, ME Tides
Show AllWhat time does the tide turn (slack tide) in Southwest Harbor, ME today?
Slack tide in Southwest Harbor, ME is approximately 11:44 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 Southwest Harbor, ME?
Southwest Harbor, ME is currently in a transitional phase. Tonight's moon is 76% 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 shifting between spring and neap.
What datum are Southwest Harbor, ME 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 Southwest Harbor, ME?
Tide predictions for Southwest Harbor, ME 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 Southwest Harbor, ME?
Tide data for Southwest Harbor, ME is sourced from NOAA Station #8413564. View the official NOAA station page at https://tidesandcurrents.noaa.gov/stationhome.html?id=8413564.
What is the moon phase in Southwest Harbor, ME tonight?
Tonight the moon over Southwest Harbor, ME is Waning Gibbous (76% illuminated). This places Southwest Harbor, ME in a transitional tide cycle, so tidal ranges are shifting between spring and neap 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.
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