It's pretty weather proof and won't run on you in the rain or snow or anything - it'll even stay on and not smudge off if you decide to not take it off with the rest of your makeup at the end of a day. I've done that a few times. Goddam it, I just love having fuller eyebrows. Did you know that the number one facial cosmetic procedure among women in NYC this year was eyebrow restoration? So funny that that's a thing now.
In any case, this Milani pencil is magic and you can get it at basically any CVS in New York. It ranges from $7 - $10, which is pretty decent, too.