long ago, when men were men, we raced in all kinds of nastiness...
probably the worst for me, relatively (since XC is supposed to be all conditions), an outdoor meet where the ice had to broken/removed for the steeplechase, the winds made the 5K into a 30/40 workout, and the friday afternoon events (remembering the DMR) were moved indoors
not exactly weather, but the 100Km race in Harrisburg PA the weekend of the TMI nuclear crisis was certainly flippin' the bird at the conditions of the day. but that wasn't my experience.