Here in Colorado, the temperatures can drop suddenly. It may be in the 70s in the middle of the day, but deep in the night, it can become quite frigid. 

While that may cause you to turn on your indoor heating system to stay warm, it may also find you stopping at the gas station more often with your car. Is it your imagination, or does winter weather really affect gas mileage? According to the Office of Energy Efficiency and Renewable Energy and the US Environmental Protection Agency, it’s not all in your mind. 

Using conventional gasoline, gas mileage will be approximately 15 percent lower at 20°F than it will be at 77°F. For your 3 to 4 mile trip running errands, it can lower as much as 24 percent in the heart of the winter. 

Don’t think your hybrid is more efficient; winter weather is actually harder on efficiency. Fuel economy can drop 30 to 35 percent when the temperatures start falling. 

What impacts your gas mileage in the winter months?

While you can’t pinpoint lower gas mileage to any one behavior, there are a variety of contributing factors that make your car less efficient. They include items both internal and external to your car. 

Road conditions

Does it seem like it takes twice as long to get to work on bad weather roads? That contributes to more gas used as you make your way down the street. You’ll also be fighting sleet, slush, and snow, which can impact the friction in the way your car handles. 

More idling

Those icy roads cause everyone on the road to slow down. Slower traffic means more idling, which reduces fuel economy. While you might not be able to avoid more idling on the highway, you can avoid idling in your driveway, and as you move throughout your errands. While it might be chilly, resist the urge to allow your car to idle your car to warm it up and keep it warm. An idling car does nothing to warm up the tires or the drivetrain – it’s for your personal satisfaction only. Even in the coldest temperatures, you can start out on your journey after turning the car on – just keep the speeds low to moderate, and don’t push the car until it warms up. Watch the temperature gauge for a good resource to know more about how well your car is handling. 

Lower tire pressure

A 10 degree change in outside temperature will equate to a 1 psi change in tire pressure. If your dashboard icon goes off more frequently in the winter months, alerting you to a tire pressure problem, this is why. Fuel economy decreases about a half-percent for every 1 psi drop in tire pressure. Keep your eye on the pressure gauge, and get your tires tested and filled frequently in the winter. 

More tire resistance

Even when your tires are properly filled, cold weather allows them to perform differently than in the heat of the summer. That’s because tires are flexible, changing shape as they perform while you drive. Sidewalls can bulge; the tread flattens as it connects with the road. But with ice and snow creating uneven patches, it impacts the shape and performance of the tires. This constant rotation combined with changing wear patterns impacts your drive … and your gas mileage. Cold, hard rubber will never perform in the same way as when it does at a more moderate temperature. 

Lower engine temperature

When your car sits in the garage or in a parking spot, the engine settles in at “room” temperature. It adjusts to the airflow around it. As the temperatures dive, the “room” temperatures change, allowing all of the engine components to cool down. To warm it back up as you turn the key, the engine calls upon a richer fuel/air mixture to engage the various parts and start the entire system working. 

Thicker motor oil

Engine oil is designed to operate no matter what temperature it is outside, but it will thicken as it cools. It takes significantly more energy to overcome the drag caused by warming up cold lubricants. Using a synthetic motor oil can help address this problem, since its viscosity is created to better handle extreme temperatures. It pays to have your motor oil changed as we move into autumn, to ensure your car is well prepared for the cooler driving conditions. 

More electrical loads

In colder temperatures, you use more of your electrical accessories:

• Lights as the daylight hours are at a minimum, and you illuminate the road in cloudy, snowy conditions. 
• Rear window defogger to help keep the back window clear.
• Heater warming up the inside of your car. 
• Heated seats and mirrors make your drive safer and more comfortable. 
• Windshield washer pump keeps your windows clean as you combat winter driving conditions. 

Winter grades of gasoline

Winter grades of gasoline have less energy when compared to the summer grades. Because gasoline doesn’t vaporize as easily at colder temperatures, gas manufacturers compensate for this by changing their formulas, creating one for cold-weather efficiency. While they may help gas evaporate easier, it reduces the combustion efficiency. 

How can you improve gas mileage in winter months?

After reading what impacts your car’s gas mileage during the winter months, it’s easy to see and build a strategy that will improve efficiency during the coldest months of the year. 

Combine your trips. Instead of running different errands each day of the week, create an “errand day” to get all of your running around completed at one time. This gives your engine a chance to warm up and stay warm as you run around town. 

Keep an eye on your tire pressure, stopping to fill them whenever they drop. 

Choose a warm place for your car. This may mean cleaning the garage, or pulling into a parking garage at night. 

Reduce time spent idling. Can you avoid the busiest parts of the day? Be prepared to leave rather than allowing your car to idle for several minutes to warm up. Warming the car is for your comfort, not your car’s. 

Clean out your car. While you should always have a winter emergency kit, leave excess personal items at home as increased weight causes further drag on the car. If you have bike racks and other accessories you won’t be using for several months, now is a good time to remove them. 

Here in Colorado, winter weather is a part of our daily lives. When the worst weather impacts us, knowing these few gas mileage tips will help you make the most of your fuel economy. 

Haven’t had your oil changed, or a winter weather inspection yet? Set up your appointment today, to ensure your vehicle is ready for the worst days.