The Chandler Burning Index (CBI) as seen below uses the air temperature and relative humidity to calculate a numerical index of fire danger.
That number is then equated to the Fire Danger severity of either extreme, very high, high, moderate, or low. It's based solely on weather conditions, with no adjustment for fuel moisture. Here on the El Dorado Weather site, the CBI is calculated from the current weather conditions and reflects the current calculated fire danger. The National Weather Service calculates a 30 day Chandler Burning Index based on forecasted weather conditions for the month.
The fire meter, & the above text are based on the SLOweather.com chandler fire index and documentation.