So tomorrow I have a delightful busy five mile walk and four hour train ride in summer.
It's hot and my hair is finally flopping into my forehead...hurray!
But I want it off my face when walking so I am thinking hair grips. The ones that snap shut.
Or does anyone have any other ideas to keep it off my face?
I'll still be in full man mode but I don't mine looking a bit silly.
Advice?

I love those little plastic "C" shaped headband that clip over the head, but you can get all kinds, including thinner black ones that are considered more or least androgynous. I live in a sunny region and wear cool looking baseball caps all the time, which work well for that. I suggest avoiding pins or clip devices, particularly metal ones, since they damage the hair. When growing out your hair you want to harm it as little as possible.

But don't be afraid to look a bit eccentric. It won't be nearly as shocking to people as when you suddenly announce you're a woman. In fact adopting a somewhat "weird" look will probably help with that in the long run. Never worry about people who stare or make rude comments about how you look. They're simply announcing themselves as people you don't need to waste your time with.

I am a trial attorney, and still not out of the closet at work.  Which means I walk into court with a ponytail in back, and two snappable hair clips on the sides to corral the hair that is not long enough yet for the ponytail.  My hair clips are maybe an inch and a half long, triangular, black in color, and I get them at Walgreens.

I've had only one comment so far from another attorney, and I just explained that I needed the clip to hold my hair out of my eyes.  No problem.

Just clip your hair back and do not worry about it.

Good old fashioned bobby pins are a little more discrete and work pretty well.