The larger the temperature swings and the higher the temperature, the faster fuel will deteriorate. Degraded fuel results in poor engine performance, less power, harder starting and lower fuel economy. Cool and consistent temperatures will prolong the storage life of your fuel. The size of fuel purchases should be limited to the amount required to seed and harvest one year's crops. There are several reasons for this.
Fresh fuel provides more energy and better efficiency.
The risk and cost of leakage, and the associated environmental liability, increase with the amount of fuel stored. So does the risk of theft. There is also the interest cost associated with owning and storing fuel. The greater the amount of fuel and the longer the storage period, the higher the interest cost. Diesel fuel should be bought in the season in which you intend to use it.