Just received a warning email not to use cruise control when it is raining. If the car hydro-planes, the speed of the tires increase and creates an airplane type effect. Anyone heard of this?
Here we go again.
The basic premise that cruise control should not be used in inclement weather is absolutely true.
The theory that the car will somehow leap into the air and fly like an airplane is absolutely false.
When you engage cruise control, you voluntarily relinquish a portion of your control over your car. Does this sound like a good idea when traction is not the best?
as they said on the other thread, the rain will not turn your car into an airplane. . .sadly. . . It’d be cool to have a flying car 
But if you have RWD, it can cause you to fishtail as the cruise control keeps the gas on when you should be letting off.
I don’t believe the issue is “inclement weather,” it has to do with the amount of traction available. I routinely use (RWD) cruse control in the rain, as long as the traction is adequate. The problem is low traction conditions that can result if you have significant standing water on the road or vary heavy rain. Most highways have reasonable drainage and using cruse control in moderate rain should not be a problem. If I feel any loss of traction, I just flip it off.