What is the typical water temperature at St. Pete Beach, Florida in October?

Answer 1

Anywhere in the Tampa side of the St.Pete's resorts is over 66.
Not the most tropical beaches though usable in the winter,
fall, summer and usually the spring. Early spring could have
some current cold from the breakdown of the ice flos way out in
the ocean. No services are shut down even then, the oldest
beach resorts are well kept. October can have storms that
bring down the overall as much as any ice storm in florida does,
generally there are some sites on the west coast that are not
cold.

Answer 2

It'll be somewhere between 78 and 83 degrees.