Hiking pants made of synthetic materials. They are superior to cotton jeans in every way honestly. I live in So Cal, and often hike in the desert, and still wear long hiking pants - but made of synthetic materials. (My goto is pants from Prana, but mainly because they have a factory outlet near me so I can get them cheap, there are other options as well) They dry out much faster than cotton, both when it comes to sweat, they don't get soaked and uncomfortable like cotton jeans, and when crossing rivers. They are much lighter than cotton jeans, and material is stretchy, allowing full range of motion when scrambling over rocks. They also last longer than jeans.

I grew up hiking and backpacking in jeans (and heavy boots), with 60+ lbs external aluminum frame packs, many decades ago, and now hike and backpack in lightweight synthetic pants and trail runners and 20 lbs base weight pack - I don't think I could ever go back.