One of two possibilities.
If the battery is low enough, it won't have the amperage to crank the motor over, but it will power the lights and everything else. I'd first try charging the battery, or if you can, pull it out and run over to an auto-parts store and have them test it. If it checks out fine, then go pull the starter out and have them test that.
It's also possible the battery terminals are just corroded. Take them off and clean them (even if they look clean) take off the negative first then the possitive and put it back on Positive first to avoid any sparking. Trust me I've seen a battery explode and it's not pretty. Use some baking soda and water and or a wire brush. I put some of those felt washers that prevent corrosion under all my batteries. If the battery is a few years old it just may be shot. Cold weather takes the power down quite a bit I see you are in NV though so it's probably not that cold It may start (if it's not dirty terminals that is) until it warms up a bit outside. Just a few things to try.