Pretty much. A couple of summers ago I stayed for a late August weekend at Hilton Head S.C. and going into the ocean was like getting into a hot tub. It was actually too warm, not at all refreshing from the 100+F day -- the Hotel pool was much cooler.
It's not unusual for this time of the year. The thing to look at is SSTA (sea surface temperature anomaly), that will tell you how much the current temperature is deviating from the long term average for this month.
The GoM gets pretty warm (I live on the water just off the GoM proper (Boca Ciega Bay)). Late summer temps in the upper 80s or low 90s are common. Our pool used to heat to 95 before the shade palms grew up.
I Don think I can recall the surface temp being less than 80 often, based on the data from my depth sonar on the boat at random times during the ‘winter’.
I wonder if we'll see a Michael situation, where Ida just continues to intensify as it closes in on land.