While the good news is that gasoline prices have been dropping over the last few weeks around the country and are now averaging approximately $3.45 a gallon, the bad news is that gasoline prices are approximately $3.45 a gallon. What that means is that millions of people across the country are still looking for ways to cut costs when it comes to gasoline and many of them are going online looking for answers.
One of the most common questions we’ve seen is one that relates to whether or not an automobile gets better gas mileage in the summer or in the winter. Some people believe that a car will get lower mileage in the winter months because gasoline is reformulated, something that car repair shops tend to agree with. The fact is however that, while a car’s mileage actually does drop slightly in the winter, it has absolutely nothing to do with the “reformulation” by oil companies of their gasoline product, it has to do with the fact that it’s colder in winter than it is in summer (duh).
The fact is, due to the cold there are a number of things that actually can lower your car’s gas mileage. The first is the tire pressure in your tires. Even if they are leak free the pressure actually drops approximately 1 pound for every 10° drop in the temperature. What that means is that if you haven’t checked your tire pressure since the last time you went to the beach, your car’s tires could already have lost significant pressure, in some cases enough to lower your mileage.
Another thing affecting your mileage is the fact that, in the cold winter months, the gasoline in your tank doesn’t burn as well. Since it’s not burning completely it means that some of it is going to waste in your cylinders and lowering your gas mileage. If you make short trips this can be more apparent because your engine doesn’t have enough time to get out of its “warm-up” mode. Instead it’s boosting your cars idle speed and using extra gasoline, something that it will stop doing what your car is warmed up after a longer trip.
People also tend to take more short car trips in the winter because of the fact that it’s so cold out. A walk to the grocery store that you would normally take in the summer is not going to be nearly as pleasurable if it’s 5° out.
So yes Virginia, there is a Santa Claus and your mom’s car is actually using a little bit more gas in winter than in summer. The fact is however that this increase is, in most cases, less than 5% and thus relatively negligible. If you find that your car is using a lot more gas in winter it might be something besides the cold weather or lack of air in your tires. In that case, take your car to your local authorized mechanic and have it checked out so that the problem doesn’t persist and your wallet doesn’t take a hit from that extra cost.