You know it's cold in south Florida when ...

[Robert Sobczak]

You know it's cold 
in Naples, Florida if ...

a. Freeze is thick enough on local canals to skate
b. Regional weather advisory recommends staying indoors
c. Out of thermal necessity you have to wear socks
d. Only a few people are still swimming in the gulf
e. c and d only

Answer:

http://www.gohydrology.org/2012/02/warm-socks-for-thermal-shock.html

[Jay]

I will have to answer E.  Although I think there should be an option for B.C.D.  :)

[Kim Gass]

I knit sox for a hobby. Next trip I should plan to stay at Watsons Place on a cold snap and bring a supply to sell. Floridians seem not to even own them. 

I could recoup gas money...

[daniel]

haha, i slept at watson's at what was probably the coldest day of 2011... where were ya??? i literally was wearing every piece of clothing i brought, including my rain gear. 

[Robert Sobczak]

I might have to put in for an order.  I agree, they would definitely be marketable if you put the right spin on them.  Vacationers from up north would proudly buy a pair just to show there friends that they bought them (and wore them) just in case when that "in the 40s" night struck.

[Robert Sobczak]

I did see some teenagers swimming in the gulf on Saturday, but it looked more like in the spirit of a dare ... not that they were actually enjoying it.

[Swamp Hunter]

It must be tough if you are not allowed to build a fire. I would be tempted. Gotta love the BCNP. You can build a fire anywhere, any time. You cant even burn anywhere in Hendry County now.

[toofaraway]

You know it's cold in Flamingo if you can hike the Rowdy Bend Trail and see no bugs.

[Robert Sobczak]

Sounds like a brutal hike on the occasions it's not.