Originally Posted by
FBinNY
You don't have to be at altitude to get cold rain, and see temperature drops of 40°, though it helps. I've gone from sweating a climb in 80°+ heat to descending in a cold mist where ice crystals would form in the hair on my legs. Likewise I've led rides where we prepared for hyperthermia, and ended up treating hypothermia.
You do need altitude, however, to have a drastic temperature drop with
every rain storm. I have never experienced a "warm" rain in Colorado. Warm before and warm after but never during.