I bought some Gap Always Skinnies in the fall (as you may recall). And then I fell and ripped the knee! No loss. They are at the seamstress now, becoming bermudas. I think the weight will be "okay" although I would not wear them on the hottest of hot days - then I would prefer a dress or skirt.
I also have a pair of denim legging jean cutoffs from the Gap last year. I like them a lot; they are lightweight, tapered and super stretchy. These I wear on almost all our days, even the hottest. But I can't find them this year. They have gone the way of the much lamented legging jean itself, I fear.
I just realized that is NO help.
How about Old Navy. I'll bet you could get an inexpensive pair of jeans there and hem to whatever length you wish. The Rock Star Leggings might work? They are not heavy fabric.