A Markov chain is used to model day to day changes in the Fire Weather Inde
x (FWI) component of the Canadian Forest Fire Weather Index System. The res
ults of statistical analyses of 26 years (1963 through 1988) of fire weathe
r data recorded at 15 fire weather stations located across the province of
Ontario suggest that it is reasonable to partition the fire season into thr
ee subseasons and model day to day changes in the Fire Weather Index class
within each subseason as a Markov chain of order 1.