I have a 582 grayhead. My egt has always stayed 1100-1150 at 5800 to 6000rpm. Today I went out for 30 minute flight and noticed a change. My egt stayed around 1200-1250. This is the first cold flight this year and not sure what to look for if anything. I was flying at 3500ft, 6000rpm, 165 deg water temp and outside air temp was -14c. When I dropped the rpm down to 3000-3500 on approach the egt dropped to 900. I have flown a dozen winters now have not noticed this before. Any comments and thoughts on this would be appreciated.

Pieter