Scrumpy, its not totally correct that it is up to the officials, ITU rules state that the water temp limit for wetsuits is 22 deg C this must be measured 1 hour before the race at three separate spots on the race course, ambient temperatures are taken into consideration when deciding if wetsuits are allowed or not, so in a nutshell, under 22 deg C wetsuit legal above 22 Deg C depends on the ambient conditions for example wind and rain
