Get More Gas In Your Tank By Fuelling Up In The Morning

TLDR; Several studies have shown that gasoline expands and contracts by 1% for every 15 degrees the temperature changes. It tends to be cooler in the morning which means the gas is more contracted and you’re getting more volume per dollar than when it’s warmer in the afternoon.

Due to the sudden surge of prices of gasoline products, many theories on how to save on gasoline spending surfaced around the world. Some stay tuned on the news for the current price of gasoline and get the chance to pump their tanks when prices are lower. However, a famous theory on filling up cars in the morning also sprouted.

Saving some bucks on gasoline expenses can give you a big amount in the long run. Other than the savings you can have, you can also greatly help the environment by minimizing pollution as well.

But what is the fact of the theory of gasoline volume and temperature relation? 

The Theory of Gasoline Volume and Temperature Relation

Many studies have shown that gasoline, may it be in liquid or gas form, expands when the temperature is higher and contracts when the temperature is lower. The gasoline expansion results in lesser energy generation, especially on hotter days. Fuel burns faster at this state.

The density of gasoline products changes based on its temperature, which in return affects its volume. Further, studies show that for every 15 degrees temperature change, the volume change is equivalent to only about 1%. 

Gassing Up

Given the stated facts, many drivers tend to fill up cars early in the morning or late at night. It is of known knowledge that at these times the temperature is colder than any other time throughout the day.

The element of truth in this theory, however, is not considered to be all true by some experts. Gasoline in pump stations is stored underground. Large highly – insulated tanks keep the gasoline and help maintain its temperature at a standard level. Gasoline temperature underground is not greatly affected by the sudden change of temperature in the atmosphere.

Nevertheless, the temperature in pump dispensers above the ground may become warmer if it sits longer time in there. 

The first few liters you pump in your tank can be warmer than that of the underground tank but as you gas up; the cooler gasoline can come up and equalize the overall gasoline temperature. The slight temperature difference during initial pumping does not greatly affect the value of the whole tank.

Yet, many experts still suggest to gas up in the morning or late at night. They stated that you should gas up at a time when the gasoline has not stayed long in sun-warmed pump dispensers. 

Also, your car should not be extremely hot when pumping as it also affects the gasoline in your tank and the pumping process. The difference can be marginal to your budget, but warm gasoline can also affect your car’s performance.


The fact may have stated that gasoline is denser in the morning and night, yet many factors can still affect the efficiency and cost-saving effect of gassing up at these times. The best time to fill up your gasoline tanks does not require you anytime within the day. 

It is still best to gas up when it is convenient for you. Going out of your way to pumping your tanks early morning or very late night may even cause you more money.