I am trying to wire a new Hunter "Just Right" thermostat (model#42995) to my old central heat and air conditioning system. The wires coming out of the wall are Red, Blue, White, and Green. On the heat /ac system itself, they are connected as follows:
Red is connected to R
Blue is connected to O
White is connected to W1/W2
Green is connected to G
My question is, which wire goes where on a new thermostat that is labeled G, W, Y, Rh, and Rc.

Red to RH (with a jumper from Rh to RC ) if you have a one transformer system
Green to G
White to W
Blue (which in most cases is yellow) to Y

I agree with wmproop. Wire it this way and you should be set.

With this said I feel a need to warn you,, with a Hunter tstat feel lucky if it lasts 6 months /a year at the most, they are junk/////if you haven`t used it yet you should trade it back in for a good Honeywell