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Summertime and the living’s easy, or so the saying goes. With higher temperatures in the summer months, have you noticed you are using more gasoline? With the price of gas at an all-time high, let’s look into how the summer weather impacts gas mileage.

How much does temperature affect gas mileage?

Gas mileage in the summer months
A car drives in front of the sun | Sebastian Gollnow/picture alliance via Getty Images

The U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy looks into this more. Oddly enough, the warmer weather can increase your fuel economy in some respects. Thanks to the higher temperatures, your engine warms up faster and runs more efficiently.

“Summer grades of gasoline can have slightly more energy; and warm air causes less aerodynamic drag than cold air.”

U.S. Department of Energy

However, it isn’t that easy. Air conditioning is a crucial piece of summer car equipment, which can lower fuel economy. Rolling down the windows might work in some areas, but other locations might be too hot for that. Weather can definitely impact gas mileage, and can even impact electric vehicle performance.

Air conditioning has a major impact on gas mileage

When it is very hot out, getting the air conditioning cranked up as soon as you get in the car seems like the only option. Unfortunately, it can have the biggest impact on gas mileage. However, it can depend on a few factors. The outside temperature, humidity, and intensity of the sun can all further impact fuel economy.

When the weather is unusually hot, the air conditioning can reduce the fuel economy in some vehicles by 25%. The fuel economy can be impacted even more during hot conditions and short trips in the car. “The AC’s effect on hybrids, plug-in hybrids, and electric vehicles (EVs) can be even larger on a percentage basis,” the Office of Renewable Energy says.

But driving with the windows down to use less air conditioning can make things worse. Having the windows down can increase aerodynamic drag or wind resistance. This makes your car, truck, or sport utility vehicle require more energy to get moving. This impact is bigger at highway speeds than it is at low speeds.

Tips to keep you cool in the summer months

If you are traveling at slower speeds, try rolling the windows down for more airflow. At highway speeds, it will benefit your fuel economy to keep the windows up and use the air conditioning. If you won’t need the air conditioning, don’t use it too much. Keeping it on a low setting will help with gas. Slowing down, in general, can help you save on gas.

Try parking in the shade or using a sunshade if you have to leave the car in the sun. It will help it stay coolers so you need less air conditioning when you get back into it.


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