A question about straightening. . .

I'm a guy with naturally wavy hair, it's cut in a bowl cut style and I wear it straight by putting some gel in it and letting my hair's weight do the rest. However, when I go out in humid weather or when I workout, it starts to get wavy and kinda frizzy. If I straighten my hair will it make it straight no matter what (water, humidity, sweat, etc.), and will it take care of the frizzies? Thanx.