I got these for when I'm on stage for rehearsals.  I wear a t shirt and have these on, so I'm not overheating, but my arms are not to chilled.

They up all the way to mid upper arm and stay in place and are not uncomfortable.  I have well-muscled arms (think bier frau - German beer waitress)

They are light and when I first put them on, I was worried that they'd be too cold (they appear very holy when on) but they were PERFECT!  as comfortable as the t shirt (in keeping me comfortable).

definitely recommend these!  They wash well, too.  I do not put them in the dryer normally - to help them last longer.  I got these in Raspberry and Olive and Burgundy - the colors are lovely!