Empirical evidence suggests that agricultural futures price movements have fat-tailed distributions and exhibit sudden and unexpected price jumps. There is also evidence that the volatility of futures prices contains a term structure depending on both calendar-time and time to maturity. This paper extends Bates (1991) jump-diffusion option pricing model by including both seasonal and maturity effects in volatility. An in-sample fit to market option prices on wheat futures shows that our model outperforms previous models considered in the literature. A numerical example illustrates the economic significance of our results for option valuation.