airport) as measured by the National Weather Service. Depending on the sensitivity of de- mand to cumulative degree-days. the utility was able to determine how much margin it would lose if seasonal temperatures deviated from the average. The degree-day threshold was determined by the utility level of risk tolerance-how much income it is willing to lose as a result of weather variability. (Most weather derivative contracts were short term with an average transaction period equal to five months.) If, at the end of the transaction period, the actual cumulative degree-days were below the established threshold, the utility would receive a payment to offset the loss in income associated with lost demand (volume) Weather protection products could take on several structures: A noor provides the customer with downside protection when the underlying variable, such as degree-days, falls below the established threshold. The upside opportunity remains unconstrained. The payout for the floor is equal to the degree-day differential times a $/dd. Most sellers of weather derivatives, however, were unwilling to accept all of the downside risk associated with a floor and therefore set a payout limit. A ceiling cap provides the customer with compensation if the underlying weather vari able goes above a predetermined level. The seller of the ceiling cap pays this compensa- tion to the buyer. A midwestern state might buy a snowfall ceiling cap that would compensate it if snowfall exceeded a certain level-this payment would help to reim- burse the state for excessive snow removal expenses. Temperature ceiling caps could be stated in degree-days or payout limits.