Wet n' Wild was open last October/November as we were there. It's plenty warm enough to swim in the water parks at that time of year - we went most days.
As far as I know Discovery Cove is open all year.
Oct/Nov 1987 Travelodge Maingate East (WDW)
1991 Anaheim (DL)
1993 Camp Davey Crockett (DLP)
1995 Hotel Cheyenne (DLP)
1996 Sequoia Lodge (DLP)
Oct 1997 Esprit Villa(WDW)
Mar 2000 Esprit Villa(WDW)
Feb 2001 Esprit Villa(WDW)
Dec 2001/Jan 2002 Esprit Villa (WDW)