June in Flagstaff is the sunniest and the warmest month of the year. In June, the weather in Flagstaff is typically warm. Average daily high temperature in June is about 25 degrees above zero. On average, Flagstaff has 28 sunny and 2 partly cloudy days in June. June as well as {{month_nom: February}}, and {{month_nom: February}} is considered the most comfortable time to visit Flagstaff.