St. Simons Island water temperature by month Swimmable from April through October.
Where these numbers come from Every number on this page is a satellite reading of the open water off St. Simons Island, not a sensor in the surf. The Georgia bight has no working water-temperature sensor anywhere along it — every candidate between Fernandina and Savannah is dead or gone.
Set beside a buoy out in open water, this record usually lands within about a degree of it; beside a pier sensor in the shallows, a degree or two out. That gap is the surf zone — shallow water moves faster than the open ocean, warmer over sun-warmed sand on a calm afternoon and cooler after a blow. Read this as the water off the beach rather than the water at your ankles.
Month by month Month Typical Feels January 54° brisk February 57° brisk March 63° brisk April 70° refreshing May 77° perfect June 81° bath-warm July 85° bath-warm August 85° bath-warm September 82° bath-warm October 74° perfect November 68° refreshing December 59° brisk
The year at a glance swimmable 40° 50° 60° 70° 80° 90° 85° 54° J F M A M J J A S O N D January: typically 54° — brisk February: typically 57° — brisk March: typically 63° — brisk April: typically 70° — refreshing May: typically 77° — perfect June: typically 81° — bath-warm July: typically 85° — bath-warm August: typically 85° — bath-warm September: typically 82° — bath-warm October: typically 74° — perfect November: typically 68° — refreshing December: typically 59° — brisk
Typical for this month Typically about 74° in October — perfect.
from the satellite record for the water off St. Simons Island
perfect
bath-warm 80° and up perfect 72–79° refreshing 65–71° brisk below 65° 74° typical for October
About this reading The satellite record for the water off St. Simons Island covers about fifteen miles of open water off this beach. Nothing is in the water here — a satellite reads the surface of that whole stretch of ocean once a day, and the surf zone itself is too narrow to appear in it.
Warm water says nothing about surf, rip currents, or bacteria — check local lifeguard flags and advisories.