"Very warm and dry conditions have been in place since last week, says Bob Henson of wunderground.com. Boulder topped out at 81 degrees (27°C) on Saturday, making it the second earliest 80-degrees reading on record."
Wildfire Near Boulder, Colorado, Prompts Evacuation of More Than 1,000 Homeshttps://weather.com/news/news/colorado-boulder-sunshine-fire-evacuations
Edit: wind, temperature, humidity, fire danger maps at the llink.
NWS: Strong winds, low humidities, and unusually warm temperatures are producing critical fire weather conditions in the South/Central Plains.https://twitter.com/nws/status/843503190448521216