Playing in the Heat

With a recent post on the ShowCardi list about a woman's dog dying of heat exhaustion, and the current heatwave we are experiencing, I thought this tidbit from today's CPE Yahoo list was worth noting.

In regarding to the question/concern, when is it too hot to play (agility, flyball, ect.)?:

This vet provided this formula for determining hot weather conditions that put your dog at risk; add the humidity percent to the temperature and if the total is 140 it is the high end of safe - the vet does not run her dogs at this figure, if the total is 150 definitely don't run your dog.