From the National Weather Service:

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
0138 AM MDT THU JUL 18 2019

…RECORD HIGH MINIMUM TEMPERATURE SET AT DENVER CO…

A RECORD HIGH MINIMUM TEMPERATURE OF 72 DEGREES WAS SET AT DENVER CO YESTERDAY. THIS BREAKS THE OLD RECORD OF 71 DEGREES SET IN 1997.