It's rainy and cold outside. (Give a piece of advice)
You should wear a raincoat. / You shouldn't... / I don't think you should...
It's really hot and sunny outside. (Give a piece of advice)
You should wear shorts. / You shouldn't... / I don't think you should...
It's freezing outside. You shouldn't wear shorts. (Accept this advice)
Good idea. / Yeah, you're right.