I had to play a gig Saturday morning.  The temps were upwards of 95 degrees and very humid.  We had to play for an hour under the blazing sun.   My fingers were sliding off the keys of the clarinet... and to try and play I had to try and hold on.  Only in trying to hold on.. I just resulted in making my hands shake uncontrollably.  I was lucky though... the woman next to me, had to be stop playing due to heat stroke, I just had to constantly shake my hands out and look forward to the end of the show.