Method and system for determining the volatility of a fuel

It is proposed a method for determining the volatility of fuel in a fuel storage system, the method comprising: - determining that a refueling event has occurred (210) and that the fuel storage system has subsequently been sealed (220); - performing a first pressure measurement (230) at a first time after the determining; - performing a second pressure measurement (240) at a second time, the second time occurring after the first time; - determining a pressure evolution rate (250) from the first pressure measurement at the first time and the second pressure measurement at the second time; and - deriving an estimation (260) of the volatility of the fuel from the pressure evolution rate.