Tides Today & Tomorrow in Grassy Key, north side, Florida Bay, FL

TIDE TIMES for Friday, August 21, 2026
The tide is currently falling in Grassy Key, north side, Florida Bay, FL.
Next low tide : in 8h 09m at 7:00 pm (0.4 ft)
Next high tide (tomorrow) : 1:34 am (0.7 ft)
Sunset today : 7:53 pm
Sunrise tomorrow : 7:00 am
Moon phase : First Quarter (65% illuminated)
Tide Station Location : Station #8723921
Common Questions About Tides

Grassy Key, north side, Florida Bay, FL Tides - Nov 1931

DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
1Sun5:561.68:200.912:001.12:260.46:305:44Third Quarter1Sun
2Mon6:541.59:351.012:481.23:340.56:315:43Third Quarter2Mon
3Tue8:101.510:381.12:081.24:410.66:315:43Third Quarter3Tue
4Wed9:411.511:241.23:551.25:400.66:325:42Third Quarter4Wed
5Thu11:071.55:261.06:290.76:335:41Waning Crescent5Thu
6Fri12:021.312:191.56:390.87:130.76:335:41Waning Crescent6Fri
7Sat12:381.51:221.57:400.57:530.86:345:40Waning Crescent7Sat
8Sun1:141.62:191.48:350.28:310.86:345:40New Moon8Sun
9Mon1:521.73:131.39:26-0.19:090.86:355:39New Moon9Mon
10Tue2:321.84:041.210:16-0.29:460.86:365:39New Moon10Tue
11Wed3:141.94:541.111:05-0.210:250.86:365:38Waxing Crescent11Wed
12Thu3:591.85:431.011:56-0.111:050.86:375:38Waxing Crescent12Thu
13Fri4:461.86:330.912:490.06:385:37Waxing Crescent13Fri
14Sat5:361.77:280.91:460.26:385:37Waxing Crescent14Sat
15Sun6:301.68:320.912:390.92:480.46:395:37First Quarter15Sun
16Mon7:311.49:431.01:501.03:510.56:405:36First Quarter16Mon
17Tue8:441.310:421.03:211.14:490.66:415:36First Quarter17Tue
18Wed10:061.211:241.14:501.05:400.76:415:36First Quarter18Wed
19Thu11:221.211:571.26:030.96:240.86:425:35Waxing Gibbous19Thu
20Fri12:241.27:030.77:020.86:435:35Waxing Gibbous20Fri
21Sat12:251.31:151.27:510.67:360.96:435:35Waxing Gibbous21Sat
22Sun12:531.41:591.18:330.48:070.96:445:35Waxing Gibbous22Sun
23Mon1:221.52:411.19:110.28:360.86:455:34Full Moon23Mon
24Tue1:531.53:211.09:460.19:040.86:455:34Full Moon24Tue
25Wed2:261.54:011.010:220.09:320.86:465:34Full Moon25Wed
26Thu3:011.54:430.910:59-0.110:020.86:475:34Full Moon26Thu
27Fri3:381.65:260.911:39-0.110:340.86:485:34Waning Gibbous27Fri
28Sat4:181.56:120.912:23-0.16:485:34Waning Gibbous28Sat
29Sun5:021.57:000.91:110.06:495:34Waning Gibbous29Sun
30Mon5:521.57:520.92:050.16:505:34Waning Gibbous30Mon
DateHigh TideLow TideSunMoonDate
AMftPMftAMftPMftRiseSet
Tidal Data Source: (8723921)

Common Questions About Grassy Key, north side, Florida Bay, FL Tides

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What time does the tide turn (slack tide) in Grassy Key, north side, Florida Bay, FL today?

Slack tide in Grassy Key, north side, Florida Bay, FL is approximately 10:17 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 Grassy Key, north side, Florida Bay, FL?

Grassy Key, north side, Florida Bay, FL is currently in a transitional phase. Tonight's moon is 65% 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 Grassy Key, north side, Florida Bay, FL 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 Grassy Key, north side, Florida Bay, FL?

Tide predictions for Grassy Key, north side, Florida Bay, FL 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 Grassy Key, north side, Florida Bay, FL?

Tide data for Grassy Key, north side, Florida Bay, FL is sourced from NOAA Station #8723921. View the official NOAA station page at https://tidesandcurrents.noaa.gov/stationhome.html?id=8723921.

What is the moon phase in Grassy Key, north side, Florida Bay, FL tonight?

Tonight the moon over Grassy Key, north side, Florida Bay, FL is First Quarter (65% illuminated). This places Grassy Key, north side, Florida Bay, FL 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.

LEARN MORE ABOUT OUR TIDE DATA