You should expect better mileage after the engine breaks in, say at 3500-4000 miles or so.
Also, as the battery undergoes more charge/discharge cycles, it'll hold more charge, thereby giving more "help" to the drivetrain, further improving your mileage - this I'm already noticing in ours which has gone about 2500 miles (4K kms) at this point.
The downside is (since you mention you live in Ohio), winter tires and cold weather (as you pointed out) both conspire to degrade mileage.
Welcome to the group, and good luck!