Does the price of gas/petrol vary due to pressure and temperature of the gas?

Technically speaking…YES it does!!! They used to tell us to always buy our gas in the coolest part of the day because IF the sun beats down on the side of your car with the tank that it can cause the gas to expand & possibly overflow thereby wasting part of what you purchased. I have seen that happen. In the summer, I try to buy my gas at night so it has time to settle before the sun comes up. I guess that early morning would also work, but I’m more of a nighttime person & buying at night is more convenient for me because I don’t like getting up early!!! It’s NOT supposed to change the volume of what you’re pumping. Instead it supposedly affects the gas itself after the fact.

Are you getting a car??? That’s 2 gas questions in a row!!!

Most gas is stored underground at a constant temperature and barometric pressure has no impact on gasoline . . .so time and barometric pressure will not impact the volume of gas put in your tank !

@Tropical_Willie What about the car’s gas tank indicator? Is there any noticeable variation on when one fills?

Does a tank of gas last longer between fills at different variables?

There’s some variation, but not a lot, and the industry has a definition of a gallon as being 60 degrees F, and no doubt the (underground, immune to daily weather variations) storage and/or pump meters are tuned to that.

Longer answer:

The gasoline companies (Shell, Exxon, Texaco, etc.) have winter formulations of gas and summer formulations of gas. read this article In particular, look at the map.

I don’t understand all the chemistry of what they are doing, but it has something to do with how gas evaporates in hot weather and causes pollution.

So…summer gas (hot weather gas) is different from winter gas, and it costs a little more.

Bottom line – it isn’t the heat that causes gas to expand and make it cost more, it is the chemistry and the gasoline companies changing the formula, and charging for it.

The gas will expand some when introduced to the fuel tank on the car. The tank has an extra amount of space so the fuel can expand without being lost due to a leak or spillage.