Siesta Key water temperature by month

Swimmable from March through December.

Month by month

Month Typical Feels
January 67° refreshing
February 68° refreshing
March 71° refreshing
April 75° perfect
May 81° bath-warm
June 85° bath-warm
July 88° bath-warm
August 89° bath-warm
September 87° bath-warm
October 82° bath-warm
November 77° perfect
December 71° refreshing

The year at a glance

swimmable 60° 70° 80° 90° 100° 89° 67° JFMAMJJASOND January: typically 67° — refreshing February: typically 68° — refreshing March: typically 71° — refreshing April: typically 75° — perfect May: typically 81° — bath-warm June: typically 85° — bath-warm July: typically 88° — bath-warm August: typically 89° — bath-warm September: typically 87° — bath-warm October: typically 82° — bath-warm November: typically 77° — perfect December: typically 71° — refreshing

The water right now

Typically about 82° in October — bath-warm.

from an offshore Gulf buoy, about 24 miles out

bath-warm

bath-warm 80° and up perfect 72–79° refreshing 65–71° brisk below 65° 82° typical for October

The quartz sand at Siesta stays cool underfoot even in August — the water is another story.

Seaweed season

The Florida Gulf coast from the Big Bend down to Naples is mostly free of sargassum, all year, however much of it is out at sea.

This is the lab's own finding rather than a quiet season: it reports this stretch mostly free of sargassum whatever the amount floating out in the Gulf. The Panhandle, west of the Big Bend, is a different coast and is not covered by it.

This is a pattern, not a forecast. The lab that watches this says plainly that predicting seaweed on an individual beach is difficult or impossible — whether it comes ashore depends on winds, tides and currents nobody can call ahead. The bulletins track how much is out there and look about a month on.

From the Sargassum Watch System, the Optical Oceanography Lab at the USF College of Marine Science. Read the current bulletin for this month's outlook.

About this reading

The reading comes from an offshore Gulf buoy riding about 24 miles out; the surf zone usually reads close to it, though sun-warmed shallows can run warmer on calm afternoons.

Reading from an offshore Gulf buoy, about 24 miles out.

Warm water says nothing about surf, rip currents, or bacteria — check local lifeguard flags and advisories.