Usually I can go about 310 or 320 miles in regular driving on a full tank.... I checked my milage today and it was 22 mpg with a lot of mixed driving..... But in the cooler months it does drop off a bit, it takes longer for the engine to heat up from cold....The last time it got down to 28-29 degrees here I got about 16 - 17 mpg instead of the 18-20 I usually get...
Milage doesnt decrease just because of cold temps, usualy becuase people will, or should, let their cars fully warm up before driving. And like me, I always forget I started the car up and it runs for like 30 minutes.