Atlantic Beach, FL water temperature by month

Swimmable from April through November.

Month by month

Month Typical Feels
January 58° brisk
February 60° brisk
March 65° refreshing
April 71° refreshing
May 78° perfect
June 81° bath-warm
July 83° bath-warm
August 85° bath-warm
September 82° bath-warm
October 76° perfect
November 70° refreshing
December 62° brisk

The year at a glance

swimmable 50° 60° 70° 80° 90° 85° 58° JFMAMJJASOND January: typically 58° — brisk February: typically 60° — brisk March: typically 65° — refreshing April: typically 71° — refreshing May: typically 78° — perfect June: typically 81° — bath-warm July: typically 83° — bath-warm August: typically 85° — bath-warm September: typically 82° — bath-warm October: typically 76° — perfect November: typically 70° — refreshing December: typically 62° — brisk

The water right now

Typically about 76° in October — perfect.

from the Mayport station at the St. Johns River mouth, about 5 miles away

perfect

bath-warm 80° and up perfect 72–79° refreshing 65–71° brisk below 65° 76° typical for October

Jellyfish and sea lice

What usually turns up on Florida's Atlantic coast, and when.

  • Stings follow the heat. Palm Beach County says jellyfish are usually more prominent in the warmer summer months. Palm Beach County's parks department — sea creatures and beach hazards
  • The Park Service says the same thing on the Space Coast — during summer months the warm water causes jellyfish and man-o-war to multiply — and adds that they travel with the currents, so they come and go seasonally. the National Park Service — safety at Canaveral National Seashore
  • In northeast Florida the two you are most likely to find on the sand are the moon jelly and the cannonball jellyfish, both most abundant during the summer season. the National Park Service — jellyfish at Fort Matanzas
  • The Portuguese man o’ war runs the other way round: the county puts it on this coast predominately during the months of November through April. Palm Beach County's parks department — sea creatures and beach hazards
  • Sea lice is not lice. It is miniature jellyfish larvae caught under bathing suits, t-shirts and even hair, which is why the rash turns up where the suit was; the itch starts hours after you get out and usually lasts two to four days. Palm Beach County's parks department — sea creatures and beach hazards
  • The larva behind it is most likely the thimble jellyfish: its eggs hatch into a drifting larva called a planula, and it is that, rather than the grown animal, which seems to be the source of the problem. UF/IFAS Extension — They call it "sea lice"

This is what a season usually looks like, not a forecast of any particular week. Jellyfish drift on wind and current, so the people who watch them say there are tendencies but no guarantees — the lifeguard flags on the day beat any calendar.

About this reading

The Mayport station at the St. Johns River mouth sits in an inlet; surf-zone water can run a few degrees off this reading.

Reading from the Mayport station at the St. Johns River mouth, about 5 miles away.

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