Ian, true, gasoline wholesalers adjust the amount of gasoline sold according to a 60 degree Farenheit standard in thr USA. Thus Wholesaler A selling 10,000 gallons at 90 degrees F to Wholesaler B knows that gasoline expands 0.069% per degree F. Thus Wholesaler B PAYS for only 9793 gallons adjusted to thr 60 degree standard. There is no such adjustment for the customer. Thus pumping 20 gallons of 90 degree gasoline at $3.50 per gallon costs the station 19.59 gallons of 60 degree gasoline or the customer has paid $1.44 EXTRA to the station.
Note that the customer always gets the correct number of gallons but the DENSITY of that fuel changes.
It is also argued that the reverse is true on cold days so in the above senerio pumping those same 20 galons on a 30 degree F day costs the station the $1.44
Also note that stations store gasoline in tanks 15 to 20 feet underground where the temp is generally a constant 55 degrees F. You can feel this during the summer as you fuel your car. As the fuel flows, you can feel the hose cool.
All in all, the technology exists to adjust for all these variables at the pump. Canada has done this since the 1970s, Hawaii uses an 80 degree standard and Minnesota prohibits any temp adjustments at any point in the sale