Don't forget these
Hi Chillindan,
One thing no one else has mentioned; all leather industrial gloves. This is for two reasons.
1) If you are going to work a cable launch site, you will have to heave steel cables about the place. These are heavy and have to be pulled hard. Cable wire invariably has strands with sharp loose ends which can scratch your hands quite badly when you get hold of the cable and start to pull.
2) Likewise, when towing a glider back or forth between the hangar and the launch point, if you are wingman during the tow then your hands will be exposed to the wind all the way to the launch point. This trek has to take place at walking pace and can easily take twenty-five minutes.
People have mentioned warm and waterproof clothing. I would agree, but add that this needs to be old clothing. With most gliders, you have to lie on your back to connect the cable, so you don't want to be lying in the mud in your best new Goretex waterproof or fleece.
I would also suggest that you check with the club whether your boots need to have a definite sole and heel, rather than the straight through combined sole/heel unit currently used in climbing/walking boots. This is because you will probably also have to drive a tractor when towing gliders and you don't want your foot slipping off the clutch or brake pedals at the wrong moment.
Have a good time!
Broomstick.