Interested in being a HS volunteer asst coach (not paid). Is it possible to do this at any HS?

Absolutely, I've done it at a couple of places, both private and public. The first was my alma mater while I got my M.A., the second was at a public school I wasn't teaching at.

Just email or call any coaches you would be intested in working with. If you get any hint that they're jerks or don't want help, move along.

Find a school nearby that's underachieving, and ask the coach if you can help. Some places might have you go through a interview process, some places you can just show up and help.

You may need to foot the bill for a background-check. Other than that they'd be glad to have you.

Many programs would welcome a volunteer coach, especially one who knows what they are doing. My son's coach in HS was an ex-collegiate distance runner and he started out the first 2 years as a volunteer, and he coached my son all the way to Foot Locker finals, and the team to state titles. The following year they hired him.

Almost all schools, because of liability issues, will require you to go through a complete background check, including fingerprints, at your own expense. BAckground checks take a while, so if you're serious about it, the sooner you start, the better.

I agree with the other posters - if you are in an area with multiple schools, just call around and talk to people. Since coaches are generally teachers, most of them won't be around over the summer, but the AD's probably will be and they could at least let you know what the school's policies are. If none of that works, show up at some early season meets and talk to people. Coaches might especially be happy if you are a runner and could run with some of the groups, or if you could volunteer to run a summer program.

You will need to go through a thorough background check. Otherwise I know at least a dozen folks on my running club who coach at local high schools.