Is It Better to Buy Fuel in the Morning or Evening?

The Temperature Myth

There is a persistent motoring myth that has been passed down for generations: "You should only buy fuel early in the morning when it is cold, because the fuel is denser and you get more bang for your buck."

The logic seems sound. Physics dictates that liquids expand when heated and contract when cooled. Therefore, a litre of cold, dense petrol should contain more energy than a litre of hot, expanded petrol. But does this actually translate to real-world savings at the pump?

The Underground Reality

While the physics is technically correct, the application is fundamentally flawed. Petrol stations do not store their fuel above ground in the hot sun. They store it in massive, double-walled tanks buried deep underground.

The temperature of the earth several meters below the surface is remarkably stable, regardless of whether it is a freezing winter morning or a sweltering summer afternoon. The temperature of the fuel sitting in those tanks barely fluctuates by more than a degree or two throughout the entire year.

The True Best Time to Buy

The time of day you physically pump the fuel has zero impact on how much energy you receive. However, the time of day does affect pricing changes.

Supermarkets and major retailers typically update their price boards late at night or very early in the morning. If you are tracking a downward trend in local prices using FindPetrol's live data, filling up in the morning ensures you are capturing the newly lowered price before the rush hour begins.

Local prices differ far more than most drivers expect. For a worked example, see current petrol prices in Bristol.

Find the cheapest petrol and diesel near you

Fuel prices change street by street, and the station you drive past out of habit is rarely the cheapest. Unleaded currently starts at 142.9p a litre against a UK average of 161.4p, across the 7,916 forecourts we track. Search your postcode to see petrol prices near me, or browse fuel prices by area to see what your town is paying.