Chickens are smart enough to get in out of the rain.
I lived on a farm as a kid and whenever it rained the chickens would get in out of the rain and go into their chicken coop to stay dry.
So as long as they can get into shelter on their own they should do so on their own.
If the chickens do get wet some it's not gonna hurt them though.
Also it's best to close the chicken coop door at night to prevent animals and other things such as rodents etc from getting to the chickens.
The chickens will remain in the chicken coop all night anyway and won't leave the chicken coop until the next morning.
So closing the chicken coop door is recommended as it protects your chickens.
Also chickens can go all night without the need for water.
When chickens go into the coop to go to sleep for the night the chickens will not leave the nest until morning.
So the chicken will not need water through the night.
As long as you keep water out for the chickens during the day then they will be just fine.
There's no need to add additional water to the chickens water bowls at night as they go all night without drinking any water.
The same is true for feed.
You only need to feed the chickens during the day.
During the night the chickens do not need feed and if you put feed out at night for the chickens it can attract rats and other animals.