The DC is a numerical rating of the moisture content of deep, compact, organic layers.
It is a useful indicator of seasonal drought and shows the likelihood of fire involving the deep duff layers and large logs.
A long period of dry weather (the system uses 52 days) is needed to dry out these fuels and affect the Drought Code.
A DC rating of 200 is high, and 300 or more is extreme indicating that fire will involve deep sub-surface and heavy fuels. Burning off should not be permitted when the DC rating is above 300.