Year-Round Fuel Choice Act of 2021 This bill amends the Clean Air Act to address the limitations on Reid vapor pressure (a measure of gasoline's volatility) that are placed on gasoline during the summer ozone season. The bill applies the Reid vapor pressure requirements that are applicable to gasoline blended with 10% ethanol (E10) to gasoline blended with more than 10% ethanol. Thus, the waiver given to E10 gasoline, which allows an increase in the Reid Vapor Pressure volatility, is extended to gasoline blended with more than 10% ethanol.