It works for a long time in the rain but eventually it will stop. That is a safety feature, by the time the rain is extremely heavy you should be controlling the car yourself.

 

Many of the technology and safety systems on modern cars, including radar cruise control, auto braking, and lane keep assist, depend on the sensors or cameras for those systems being in a clean state. As dirt or even lots of water accumulates during a heavy rain, those systems can stop working.

 

Using cruise control in heavy rain is frowned upon!

 

why?

 

If vehicle hydroplanes, cruise will attempt to maintain current speed even though speed and traction has decreased possibly causing loss of control. Page 273 of owners manual.

 

Was traveling on an expressway several months ago during a heavy downpour. Posted speed limit was 100 km/h but this road is notorious for speeding and accidents. Car passed me and shortly after lost control and ended up on the medium a few feet from apposing lane. I pulled off the road to offer assistance and luckily they were OK. Noticed toddler strapped in car seat and commented to driver in as friendly manner as i could muster. "You might want slow down a bit when the roads are wet and slick". Reply: "I was only doing a 100"!

 

Sometimes in rainy conditions (we are very used to here) someone passes and gives a “splash”. Frequently thats the moment that the acc stops.

I’m surprised with the different demeaning comments shared here. I’m safe driver and never had an accident. Hopefully other can reflect how to share. That’s just polite 101.