Grassy Key water temp

This data the coastal Grassy Key ocean water temperature today, tomorrow and the upcoming days. Besides, you can also get information about the weather and surf forecast, as well as the data on sunrise / sunset and moonrise / moonset at a given point on any given day.

Current ocean temperature in Grassy Key

Water temperature in Grassy Key today is 88°F. Based on our historical data over a period of ten years, the warmest water in this day in Grassy Key was, like today, 88°F, and the coldest was recorded in 2008 at 84.2°F. Sea water temperature in Grassy Key is expected to drop to 85.6°F in the next 10 days. September average water temperature in Grassy Key is 85.6°F, the minimum temperature is 82.9°F, and the maximum is 88.9°F.

The swimming season in Grassy Key lasts from January to December, twelve months per year! During those months, Grassy Key water temperature does not drop below 68°F and therefore suitable for comfortable swimming. The average water temperature in Grassy Key in winter reaches 76.1°F, in spring 78.8°F, in summer the average temperature rises to 85.6°F, and in autumn it is 82.9°F.

Grassy Key water temperature now

Surf Forecast in Grassy Key for today

Another important indicators for a comfortable holiday on the beach are the presence and height of the waves, as well as the speed and direction of the wind. Please find below data on the swell size for Grassy Key. We calculate the swell size based on the mean wave height (trough to crest) of each third highest wave. For more information on surf forecasts for the next ten days, please visit sea state forecast Grassy Key. Data in table shown for September 5, 2025, time in GMT 0 format (you can change the time zone on the sea state forecast page)

Surf report in Grassy Key

Grassy Key weather forecast

Current temperature and weather

Data in a table show Grassy Key temperature today (September 5, 2025). For more information and forecast for a few days, go to the weather forecast Grassy Key.

0-3 h	3-6 h	6-9 h	9-12 h
80.2°F	81.5°F	82.2°F	82.6°F

12-15 h	15-18 h	18-21 h	21-24 h
80.6°F	80.8°F	79.9°F	78.8°F

Grassy Key water temperature by month

These figures shows the average, minimum and maximum monthly sea temperature in Grassy Key. In addition to the table values, the graph below displays of changes average surface temperature during the year. Values are calculated based on the data over the past 10 years. Using them, you can check the water temperature in Grassy Key on any day of this period that interests you. Click on the month link and you will see a table for each day, or alternatively you can view the temperature curve of the month and select 2 different years you want to compare, either in a table or as a curve

Chart monthly average water temperature in Grassy Key

The most popular beaches and cities in Florida with sea temperature today, weather, air temperature and sea state (wave height)

	Water	Weather		Wave
Sarasota	86°F	86°F		1' 1"
Key West	87.8°F	84.2°F		2' 8"
Naples	87.6°F	80.6°F		1' 2"
Miami Beach	87.1°F	82.4°F		1' 5"
Fort Myers Beach	87.3°F	82.4°F		1' 1"
Destin	83.5°F	87.8°F		0' 6"
Fort Lauderdale	87.3°F	82.4°F		2' 0"
Key Largo	87.4°F	82.4°F		1' 7"
Cocoa Beach	85.3°F	84.2°F		1' 1"
Clearwater Beach	84.6°F	87.8°F		0' 10"

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Our report for Grassy Key is compiled using satellite data together with in-situ observations to get the most reliable daily data of sea surface temperatures, surf forecasts, current temperatures and weather forecasts.