I'm heading to Hawaii in a few weeks. When I play over there, the ball seems to move through the air faster than it does in California. If this is due to the humidity in the air, which way would you go with string tension to keep your power, spin and control?
I would think that multis and especially gut are prone to humid conditions. It depends on the protective coating. Gut now has better coating protection lately and can last. But I would string the racquet tighter to keep control of the faster ball. You will lose power, and you will have to swing harder for spin, but go tighter. The humidity is going to soften the string up, which is the less extreme version of hitting wet balls in the rain.
Gut will hold its tension best in humid conditions; some even have a thermoguard technology. Multifilaments, synthetic guts and polyesters will hold tension worse in humid conditions (though Luxilon used to claim their strings are impervious to changes in temperature/humidity, not sure if they still do). In hotter, more humid conditions I would always string a little tighter.
I would've never thought gut would be good in any type of moisture. I remember the days of having to shield the gut from any water contact in stormy weather. I do believe the thermoguard VS uses truly works, but is it that the fibers are better off not being in dry heat with high temperatures?