I used to skydive many moons ago where wind and low cloud cover used to be problematic (it was the UK after all) and suspend activity. However, in a similar vein to the post above, "If you're on the drop zone, you might jump, if you aren't, you won't!"
I was fortunate enough to be at Speed Week 2011, I concur. Whilst the rain and wind was bad at the end of one of the days, record back-up runs were being carried out the very next morning (although that was after having driven through a newly formed salt lake for a bit at Land's End to get to the pits). Was the salt ideal the next day, probably not, but the courses were open and racing was on.