There is a huge difference down south,the air isnt as dry as the north, besides that if you are at the winternationals chances are you have a spare engine with you,and alot more money involved, It is touchy if you are running all aluminum tho, but like rocky said take steps to protect, its a gamble.
I wondered about this since I have been in both places several times. There is not nearly as much difference in the humidity as one might think. Links are provided for verification.
Pittsburgh in October: LINK>>
Humidity
The relative humidity typically ranges from 47% (comfortable) to 91% (very humid) over the course of a typical October, rarely dropping below 30% (dry) and reaching as high as 100% (very humid).
The air is driest around October 24, at which time the relative humidity drops below 55% (mildly humid) three days out of four; it is most humid around October 1, rising above 87% (very humid) three days out of four.
Tampa in February: LINK>>
Humidity
The relative humidity typically ranges from 50% (comfortable) to 92% (very humid) over the course of a typical February, rarely dropping below 28% (dry) and reaching as high as 100% (very humid).
The air is driest around February 29, at which time the relative humidity drops below 60% (mildly humid) three days out of four; it is most humid around February 1, rising above 88% (very humid) three days out of four.