I have really fine hair, and in this weather (wet / windy) it is getting really messed up. If I go out I end up looking like a drowned rat, and by the time it's dried out again it frizzes all over the place.

Are there any good treatments out there to stop hair frizzing? I used to use a serum but the hairdressers have stopped stocking it, and the gels don't seem to work as well :(