Recently when starting my engine, I've had to richen the low end about 1/4 turn more than it had been during the summer. I had to richen it even further today after a dryline came through and dropped our relative humidity to very low values. Is this normal? Do gas engines generally need richening in drier air. Also what about colder conditions. Does it need to be at a richer setting in colder weather than in warmer weather. Colder air holds less water vapor than warmer air.

Thanks,

Greg