In the swap, Enron agreed to pay the billing service for heating degree days above a certain amount, and get paid for every heating degree day below a certain amount.

FORBES: Betting against God

This contract was pegged to heating degree days in St.

FORBES: Betting against God

Heating degree days are a measure of how long and how far the temperature stays below 65 degrees, that being the point at which people reach for their thermostats.

FORBES: Betting against God

The problem with the natural gas market is that it is highly inelastic and is subject to massive swings in demand with the degree heating and degree cooling days on a region or even continent.

FORBES: We're Headed To $8 Natural Gas