Get gas early in the morning. It expands with heat and you get less per "gallon" when it's hot out.
Temperature of Gasoline Affects Price: Hotter Equals Billions More
People residing in hotter climates may be dismayed to know that you may be pumping your car full of hot air, literally. Although rarely considered, it's simple physics-- as gasoline heats up in the storage tanks, it expands, becoming less dense.
Even the time of day you pump your gas can have an impact; times such as early morning are when the gas will in effect, be cheaper for the average motorist. The difference per visit is very slight, but over a year, it can add up.
In fact, U.S. consumers in their entirety are estimated to overpay for "hot air" gasoline to the sum of a whopping $2.5 billion. Gasoline stations could adjust their pumps to compensate, but cite the "expense" of the necessary retrofitting required.
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