Some of the hiking pants are pretty hard to tell from just casual pants. Kuhl is a good one for that category with lighter fabrics. You might also look at things sold more as travel pants, like Eddie Bauer. I'm sure someone will recommend lightweight "tacticool" pants, but those are not really any cooler than jeans to me and likely not appropriate for an office job. Some of Dickie's stuff is lighter. Not the most stylish and the durability is variable. Uniqlo might also work as being slightly more durable than your average mall store, but don't expect to do hard labour in them. More offbeat suggestion - Utilikilt. There are also some other good sport kilt makers out there, but very much if it seems too cheap to be true, it probably is.

Wrangler atg pants.

Cotton or cotton blend khakis are much more comfortable than jeans in the summer.

I always got them from Gap or Old Navy and they would last maybe 5 years.

Golf trousers are the way to go.

Orvis makes some delightful lightweight pants. I guess they're technically hiking pants, but they're super comfy and don't have all the cargo pockets and extra zippers that some hiking pants have.

Anything that has stretch in it will feel a hell of a lot hotter, unfortunately, so rule them out immediately. The best pants for hot weather that I’ve found are light colored linen pants. Like you aren’t even wearing them. The downside is that they aren’t the best looking and they wrinkle easily. But they are like nothing else.

Linen trousers?

Prana Brion

What activity goes on outside? How durable do they need to be?

PublicRec

There are no comfortable pants in the sun. Jeans is all I wear during the summer.