National Weather Service United States Department of Commerce
Dispersion Index Table


Dispersion Index Interpretation
>100 Very Good (but may indirectly indicate hazardous conditions.)
60-100 Good (typical burning values)
41-60 Fair to Good (climatological afternoon values for most inland forests.)
21-40 Fair (stagnation if accompanied by persistent low wind speeds.)
13-20 Poor to Fair (stagnation, if persistent; better than average for nighttime.)
7-12 Poor (stagnant, but near average at nighttime.)
1-6 Very Poor (climatological nighttime value for most locations.)