I understand it doesn’t have to be “cold” but colder only makes a bad set of circumstances accelerate.Temperatures aren't really even as big a factor in turkey poult survival as just the number of day of rain over the summer months of June, July and August. It can be pretty darn warm and young turkeys just walking through wet grass will soon be dead if they get wet and hen can't brood them. That hypothetic shock can, and often will, affect them and have them paralyzed and near death in just a matter of a few minutes.
I don’t know how a turkey poults ever stays dry. Walk around in your sneakers and long pants any morning as the sun comes up and watch how quickly your pants get soaked from the morning dew.
If they can die in a matter of minutes from getting wet even in warm weather, how do any of them ever survive? Unless they wait until the sun burns the dew off every morning before they move, how do they ever stay dry and not die?
I remember seeing a hen with a pile of poults just a few days old. That night we had torrential downpours, straight line winds and temps plummeted. I figured that batch was a gone. Didn’t even give them a chance of making it. Yet the next day she had them all fluffed up and tripping over each other to kee up with her. I was blown away. All I could figure was she headed for a cedar thicket and squatted all night.