That one definitely makes me cringe every time I read it.
First of all, if I could predict the weather in three months time, I wouldn't be sitting here working...
Second of all, weather and comfort levels are so subjective. Things like will we be able to swim, will it be warm enough to wear shorts, what kind of clothes do I bring, etc. totally depend on the individual and what kind of weather can they tolerate.
I work outside a lot, so I tolerate the weather a lot better than others. I go the week after Thanksgiving and I can be comfortable in a lightweight hoodie at night, while people around me are wearing coats or chattering their teeth. Some people will still be wearing shorts.
And the swimming part - if you can stand the run back to the room soaking wet, then go for it.
It mystifies me to no end that people cannot look at the weather a few days ahead of time, and say, hey, it is going to be 50 degrees at night, what do I wear at home that gives me the same comfort level I want to have in Florida.