Windpants in Fall

especially since i seldom carry waterproof shell pants. depending on where i am and what i'm doing my cool/cold weather bottom half kit is comprised of underarmor heatgeat shorts, running tights, gym shorts and wind pants. mixing and matching you can pretty-much go anywhere from hot weather to the single digit (while on the move) temperatures.

Windpants:
They are very light.
They take up very little space in your pack.
They provide a lot of warmth for their weight.
They can be worn instead of your hiking pants when doing laundry or making repairs.
They shed most rain. In fact I use them instead of rain pants.
Many more reasons…

They are not a frivolous item and are multi-use.

Windpants have all the positive attributes as windshirts except for the fact that they are exposed to more dirt and abrasion than tops. You really need to be hyper-aware of you surroundings if you don't want to shred them.

I think they have a good weight/utility factor when used with SUL shorts like running shorts; otherwise zip-offs give good utility over a wide range of conditions with better durability. They should offer zip offs with really high DWR to help bridge the gaps.

IMHO, the pants for cool/wet Fall and Spring weather are light soft shells. I wish they made more with lighter colors— with most being black, they get hot in a hurry when the sun breaks out. Even with that you get very good DWR, breathability, warmth and they are very comfortable.

Another compromise is to use nylon runner's "track" or "warmup" pants. Unlined models usually weigh about 6oz and they are a step up in durability and water resistance and they can be cheap. In fact, you can find ones that are pretty much rain shells minus the seam taping.

Good point about the runners pants. They can be had at discount sports stores for much less than wind pants. You won't mind the cost of replacement as much when you wear them out.

I will say that my wind pants have held up surprisingly well for how thin they are, but I haven't done much bushwhacking or major scrambles in them.
I always take them off for the rough stuff.

If you live in a big city, thrift stores usually have a ton of good running pants. I've been surprised that they haven't had more popularity in the UL world– kind of like DriDucks rain gear– cheap and light.

This would be my system, but I don't want to buy wind pants.

I use hiking shorts (MH Ultrarunning shorts), A Smartwool pair of tights, a Smartwool pair of briefs for support, and some GoLite Rain Pants.

I use the rain pants as "It's much colder than I expected" pants and can go all the way down pretty far in temperature. Probably 25º or lower if I'm moving. They're also fantastic for camp to keep off mosquitos.

But yes, I agree with your system and your logic completely.