Conditions in winter put a significant strain on your car and on your driving. Winter can also put a strain on your fuel mileage.  To prevent a decrease in your gas mileage you need to address some specific issues with regard to winter driving and your car.

The main characteristic of winter, cold temperatures, can increase your gas usage significantly.  A car that is cold uses more gas at start up than a warm car.  The lower the temperature the more gas a car has to use when it starts.

A car's engine is harder to start at low temperatures. The cold causes the oil in engine to thicken. The thicker oil necessitates more energy to get it flowing. Any time more energy is required more fuel is also required.  Even after you have started the engine, it will use more fuel until it reaches operating temperature.

Other parts of the car are affected by the cold. The joints, transmission, bearings,  brakes, and steering mechanisms all need more energy to move them in cold temperatures.  This is partly because they too use fluids in their operation that thickens in the cold.  Subsequently more energy is needed to operate them which also burns more gas.

Other parts of your car will be stiff and may be frozen. Moisture in the air can condense and freeze on many car parts. Water from precipitation or from the road may have frozen on to part of the car. It will take more energy to move these parts.  Wheel bearings, suspension systems and wheels themselves are some of the parts effected. The same applies, more energy needed to move these parts translates into more fuel burned and lower gas mileage.

Since your engine needs to overcome some temperature issues to lubricate itself in the cold you do need to give it a little longer to idle after starting than you would in the summer.  But, I have to stress this, it only needs about 30 seconds of idling, no more.  That little extra idling does affect your gas mileage.

Some things you can do to mitigate the affects of cold on gas mileage are: Park your car in a heated garage if available.  Even a non heated garage may be warmer than leaving your car outside.  It may be time to get rid of all the boxes in your garage and make room for your car.

Always make sure you have the proper oil for operating your car in the cold. The right oil will be thinner and will flow easier in cold temperatures. The proper oil will require less energy to start and flow and therefore will require less fuel.

In extreme cold climates an engine block heater will help keep the engine and oil warm thus avoiding a complete cold start.  You will need a way to plug it in and keep it plugged in until you are ready to drive.

Don't wast fuel warming your car when you start it.  You only need about 30 seconds of idling to make sure the oil is flowing sufficiently in the engine.  Excessive idling beyond 30 seconds will rob you of gas mileage faster than anything else.  Let the car continue to warm up as you are driving.

Although cold temperatures can greatly reduce gas mileage, you can minimize or eliminate it's affect. Just follow the simple steps outlined here and you can maintain good gas mileage.