Greenmachine,

High humidity does not increase wind resistance; it actually makes the bonds between air molecules weaker and reduces the effective density of the fluid. This is why humidity contributes to density altitude considerations for aircraft load and balance. On hot 'n' humid days, you may want to pull a jumper or two out of the doghouse of that Otter...

Cheers,

Chris

Edited to add:
distance = 1/2*a*t^2
d = 1/2 (9.8 * 16)
d = 78.4 meters
78.4 meters = 257.2 feet