Seasonal Octane Specifications

Petroleum marketers traditionally supply gasolines of constant octane quality year-round. However, car octane number requirements are not constant, but vary with atmospheric temperature and humidity. Adjusting octane quality to match seasonal changes in car requirements would result in less octane giveaway during periods of low requirements and would reduce gasoline manufacturing costs for the same year-round satisfaction. Because of problems with exchanges, contract sales, and pipeline fungibility specifications, application of seasonal octane specifications on a widespread basis is not feasible unless they are generally accepted by the industry.