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

TIDE TIMES for Monday, September 21, 2026
The tide is currently falling in Grassy Key, north side, Florida Bay, FL.

Next low tide : in 4h 16m at 8:20 pm (0.7 ft)
Next high tide (tomorrow) : 2:05 am (1.0 ft)
Sunset today : 7:21 pm
Sunrise tomorrow : 7:12 am
Moon phase : Waxing Gibbous (75% illuminated)
Tide Station Location : Station #8723921
Common Questions About Tides

Grassy Key, north side, Florida Bay, FL Tides - Mar 1868

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Apr 1868 >

Date		High Tide				Low Tide				Sun		Moon	Date
Date		AM	ft	PM	ft	AM	ft	PM	ft	Rise	Set	Moon	Date
1	Sun	8:17	0.6	7:55	1.0	2:49	-0.2	2:21	0.2	6:49	6:30		1	Sun
2	Mon	9:43	0.5	9:03	1.0	4:00	-0.2	3:20	0.3	6:48	6:30		2	Mon
3	Tue	11:16	0.5	10:25	1.0	5:16	-0.2	4:34	0.3	6:48	6:31		3	Tue
4	Wed			12:28	0.6	6:28	-0.3	5:51	0.3	6:47	6:31		4	Wed
5	Thu			1:21	0.6	7:31	-0.4	7:02	0.2	6:46	6:32		5	Thu
6	Fri	12:51	1.2	2:05	0.7	8:25	-0.4	8:04	0.0	6:45	6:32		6	Fri
7	Sat	1:50	1.3	2:45	0.9	9:11	-0.4	9:00	-0.1	6:44	6:33		7	Sat
8	Sun	2:45	1.3	3:23	1.0	9:54	-0.4	9:51	-0.3	6:43	6:33		8	Sun
9	Mon	3:35	1.3	4:00	1.0	10:33	-0.3	10:41	-0.4	6:42	6:34		9	Mon
10	Tue	4:23	1.2	4:37	1.1	11:12	-0.2	11:30	-0.4	6:41	6:34		10	Tue
11	Wed	5:10	1.1	5:13	1.1	11:50	-0.1			6:40	6:35		11	Wed
12	Thu	5:55	1.0	5:50	1.1	12:20	-0.4	12:29	0.0	6:39	6:35		12	Thu
13	Fri	6:42	0.8	6:29	1.1	1:13	-0.3	1:09	0.2	6:38	6:36		13	Fri
14	Sat	7:33	0.7	7:12	1.0	2:09	-0.2	1:52	0.3	6:37	6:36		14	Sat
15	Sun	8:36	0.6	8:03	1.0	3:11	-0.1	2:44	0.4	6:36	6:37		15	Sun
16	Mon	10:07	0.5	9:08	0.9	4:18	0.0	3:49	0.5	6:35	6:37		16	Mon
17	Tue	11:44	0.5	10:26	0.9	5:28	0.0	5:04	0.5	6:34	6:37		17	Tue
18	Wed			12:42	0.6	6:33	0.0	6:15	0.5	6:33	6:38		18	Wed
19	Thu			1:18	0.7	7:28	0.0	7:15	0.4	6:32	6:38		19	Thu
20	Fri	12:36	1.0	1:47	0.7	8:12	0.0	8:04	0.3	6:31	6:39		20	Fri
21	Sat	1:24	1.0	2:14	0.8	8:48	0.0	8:45	0.2	6:30	6:39		21	Sat
22	Sun	2:07	1.1	2:41	0.9	9:20	0.0	9:22	0.1	6:29	6:40		22	Sun
23	Mon	2:47	1.1	3:10	1.0	9:49	0.0	9:58	0.0	6:28	6:40		23	Mon
24	Tue	3:27	1.1	3:39	1.1	10:18	0.0	10:34	-0.2	6:26	6:40		24	Tue
25	Wed	4:08	1.1	4:10	1.1	10:46	0.0	11:12	-0.2	6:25	6:41		25	Wed
26	Thu	4:49	1.0	4:42	1.2	11:16	0.1	11:53	-0.3	6:24	6:41		26	Thu
27	Fri	5:32	0.9	5:15	1.2	11:48	0.2			6:23	6:42		27	Fri
28	Sat	6:19	0.8	5:52	1.2	12:39	-0.3	12:23	0.2	6:22	6:42		28	Sat
29	Sun	7:12	0.7	6:35	1.2	1:32	-0.3	1:04	0.3	6:21	6:42		29	Sun
30	Mon	8:17	0.7	7:29	1.1	2:33	-0.2	1:54	0.4	6:20	6:43		30	Mon
31	Tue	9:38	0.6	8:42	1.1	3:42	-0.2	3:02	0.5	6:19	6:43		31	Tue
Date		High Tide				Low Tide				Sun		Moon	Date
Date		AM	ft	PM	ft	AM	ft	PM	ft	Rise	Set	Moon	Date

Tidal Data Source: (8723921)

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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 75% 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 Waxing Gibbous (75% 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

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