The other possibility is the gas itself, not the regulator.
In southern areas a lot of gas distributors will sell butane, or a butane propane blend in warm weather.
At 70 degrees there's really no difference between the two, but since the gas vapour that appliances burn is the result of the liquid boiling, cold weather can render butane or blended gas useless.
Propane boils at anything warmer than -43 deg. F.
Butane boils at anything warmer than +30 deg. F.
So if you're using butane and the temperature drops below freezing you will have no gas unless you can keep it warm.