So is there any truth to this? Is it dangerous to drive in the rain with cruise control activated? Not according to Australia's RAA (Royal Automobile Association) which recently issued an advisory about this email:
“Should the car’s tyres break traction with the road, such as in an aquaplane situation, the increase in wheel speed would be sensed and the cruise control system would then reduce the amount of throttle and maintain the set speed. Additionally, cruise control systems are deactivated as soon as the brake is applied. As braking is usually an automatic reaction in most emergency situations, the scenario of cruise control causing an increase in vehicle speed is highly unlikely.”
I actually never use cruise control, whether or not it's raining, because I have a bit of a phobia about it. I have a fear that one time I'll step on the brake, and the cruise control won't deactivate.