This page provides access to past years of an experimental fire weather monitoring product called the Burn Period Tracker. Burn period is defined as the number of hours per day where the hourly average relative humidity is less than or equal to 20% and is calculated at Remote Automatic Weather Stations with real-time data and several years of historical data. Values range from 0 to 24 hours per day with higher values associated with increased fire danger.
Climate Science Applications Program - University of Arizona Cooperative Extension
https://github.com/Climate-Science-Applications-Program/Burn-Period-Tracker