It depends.. If its dark , then no..... But if you wear the glasses like fisherman wear to see into the water then yes.. This is because it removes glare. But that is the extent of it. So dont go "wearing your sunglasses at night" ...because it will only hinder your vision!!!
I think you'd better not wear a pair of sunglasses when you are driving during a rainstorm, because it is very dark during the rainstorm. The lenses of the sunglasses can make the environment darker. Maybe you can't see the things around clearly. It may lead to an accident.
Sunglasses can't improve your vision at that moment. Though they are a pair of prescription sunglasses, they can't improve your vision, let alone a pair of Plano sunglasses. Because the tinted lenses will darker the things around you, you can't see things clearly.
It is very dark during a rainstorm. You'd better not wear the sunglasses at that time. If you don't have very serious vision problems, you can drive with your bare eyes. Open the head lamp and tail-lamp so that other drivers on the same road can notice you. Besides, you should drive more slowly than usual. But I still suggest you to put a pair of prescription glasses in your car in case that you can't use your sunglasses during a rainstorm. Hope this helped!
Driving with a pair of sunglasses in a sunny day can protect your eyes from the UV rays as well as glare from the sun or smooth surface of other objects. But it is quite dark during a rainstorm. If your sunglasses filter 70% of the light at this moment, you can hardly see things clearly. This may lead to an accident. If you can't find other ways to improve your vision (by glasses) or can't ask other people to drive for you, you'd better give up driving. If is safer to stay in the car than take the risk to drive in a rainstorm.