Rain pants. Now there’s a topic that I am sure many of us have different opinions about!
I almost always wear my rain pants over my hiking pants, except when I am doing laundry in a trail town and rain pants are the only pants I am wearing!
Joking aside, I wear my rain pants over my hiking pants because it’s much easier to put them on and take them off when it starts and stops raining. Think about what a hassle it would be to switch between the two every time it started or stopped raining during the day.
I also wear hiking pants under rain pants because they slow body heat loss when my outer layer is wet. It’s the same reason I wear a fleece sweater or mid-layer under a rain shell in the rain, because it keeps the cold shell fabric off my skin where it can rapidly chill me.
I know a lot of people who don’t hike with rain pants at all. This is really a regional issue; New England weather tends to be much wetter than many places in the western USA where it doesn’t rain or doesn’t rain enough. That’s why I always carry rain pants on hikes, even on dayhikes.