Why Fuel Economy of Cars is Worse in Winter Than in Summer

The average fuel efficiency of my Mercedes-Benz C320 '03 on highways is 28-30 miles per gallon (MPG). This is something that I have sometimes measured during my summer trips, however, during this weekend that I traveled to Atlanta, GA, which is about 400 miles away from where I live, I noticed that the average MPG-Highway of my car on this trip was only 22-24 and it really scared me and made me think that my cheap Mercedes needs to visit the workshop.

I couldn't believe how poor the gas consumption of my car was during this trip to Georgia, so I decided to Google something about it and found out why the fuel efficiency or fuel economy of my car was so poor during this trip thanks to a great article from topspeedracer.com where they explain why cars get better gas mileage in summer than in winter or in my case, why my car has poor fuel efficiency in cold weather or winter than in summer.

So, this is a brief summary of the many factors that cause that in general, vehicles to get fewer miles per gallon during winter and cold climates, especially gasoline cars, which are those that topspeedracer.com article is focused on.

Air Pressure of Tires

During cold weather, tires lose air pressure because they shrink, so as the air temperature drops, so does the air pressure in your tires, concludes Rick Popely from Ask.Cars.com in the article: Why do I lose pressure on my tires during cold spells?. Tires with less than the number of air pounds that they should have, increase rolling resistance and decrease the fuel efficiency of your vehicle. In warm climates like spring and summer, tires gain air pressure, the rolling resistance decreases and it helps to get better miles per gallon (MPG).

Warm-Up Time of The Engine

Cars these days get the best performance on fuel economy when they are working at their normal temperature. During winter and cold weather, your car takes longer to achieve its ideal operating temperature and it results in decreased fuel efficiency. When the weather is hot or warm outside your vehicle needs less time to achieve its normal operating temperature helping to save gas and improving fuel efficiency.

Oil Thickness

Oil viscosity or thickness is affected by temperature. Heat makes it thinner and reduces drag on the engine and increases the fuel efficiency of your car. Cold weather does the opposite. The engine of your car operates better when the oil flows like water. It also applies to most of the fluids in the car.

The Density of Air

Cold air is denser than hot air. What does it mean? Your vehicle when in motion will have to fight harder with the outside air resistance and hence you will have to accelerate it more as well for this reason it will have better fuel economy during summer and high outside temperature conditions. If you want to have an idea why cold air is denser than hot air, please check the link.

Vehicle Maintenance

Most people prefer to tune up and do regular maintenance to their cars during the spring and summer to face the traveling season with "safety-first" in mind. During cold or winter weather, people tend to be lazier at the time of taking the car to the workshop and everybody knows that a vehicle periodically well-maintained, yields better fuel efficiency than those who only visit the mechanic every 6 months or more.

Winter Grade Gasoline

There are states in the country that require gas stations to sell oxygenated, reformulated, or blended gasoline during cold weather season. These types of fuel contain ethanol or butane compounds that cause lower gasoline yields by 1% to 3% due to their lower energy content. Fuel sold in summer and spring usually has a higher energy content, therefore during these seasons, your vehicle will get better gas mileage.

Ice, Snow & Road Conditions

During cold weather and depending on where you live, snow and ice can present slippery road conditions causing wheel spin upon acceleration. During these feats or when you are trying to get out of certain icy spots, you have to accelerate more your car and this will reduce the fuel economy of this one. Cold weather and icy roads also obligate you to drive carefully and at lower speeds and this will decrease the fuel efficiency of the car.

Engine Ignition

Starting a car in cold weather takes longer than in warm weather. If you have a poorly maintained car, it will take even longer. Usually, during summer, cars take less time to start up and it helps to improve gas mileage.

Increased Alternator Demand

Usually, during winter you tend to use the instruments and accessories of your vehicle like the heater, windshield wipers, seat heaters, windshield defroster, lights, etc. All this demands more power from the alternator of your car and this additional drag on the motor will increase the gas consumption of your car.


So, these are some of the reasons why your car gets better fuel efficiency during summer and hot weather than in winter and cold weather . If you have paid attention to this and you know the MPG difference of your car during the weather stations, we'd love to have you share the figures. If you know any other reason why cars get poor fuel economy during winter, we'd love to hear it.

I think I get worse miles per gallon during winter mainly because I love to spin the wheels of my car But anyway, it is great to know this, very valuable information John. Best car deals and a lot of affordable pre-owned vehicle available! Love it!

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Wonderful! Now I can understand why I have been about 30% more in gas during these last two months, I can't wait until this freaking cold weather ends... hurry up spring!!!! "When girls go wild, they show their tits. When women go wild, they kill men and drown their kids in a tub." ;D