It’s normal for the distance you can drive on a full tank of fuel to go up and down throughout the year as the weather gets warmer and colder and impacts your mileage. For most of us, the Volt is the first car we’ve driven whose main fuel tank (the battery) holds only the equivalent of one gallon’s worth of driving distance. We’re not accustomed to seeing a "start of the morning" estimate of how far we’re likely to drive before the tank is empty, so when that estimate heads down to the bottom of the annual cycle as winter arrives, we’re flabbergasted. Does the mileage really drop that far? Yes, it can (especially in cold climates). Dealing with it "one gallon's worth of distance" at a time magnifies the astonishment.
We tend to forget, too, the end of daylight savings time in the fall triggers changes in the ambient temperatures and daylight we experience as we commute to work and back, causing increases in the portion of battery power used for lights, wipers, window defrosting, and cabin heat, and decreases in the portion available for propulsion.
