Flagstaff weather in August

Forum posters cite an average March daytime high around 43F with nighttime lows in the teens, describing March as still genuinely winter in Flagstaff - posters are direct that snow at some point during the month is close to guaranteed, unless an unusually warm stretch arrives early. Posters describe a typical late-winter snowfall here as brief, usually gone within a day or two, with roads cleared quickly except during a major storm, which can shut down travel for several days at a time. Posters consistently recommend monitoring forecasts roughly a week ahead and building real flexibility into a March itinerary. Posters generally rate March as a high-precipitation, snow-capable month, workable for a visit but requiring genuine weather-contingency planning.

Late September into early October is the window regulars name for this part of Arizona: temperatures cooling, patterns fairly stable and mostly sunny, crowds thinning. Flagstaff sits at about 7,000 feet, which is the whole point — days near 25°C while the desert below is still hot, and nights dropping to about 13, cold enough that a jacket or fleece is wanted early and late, with freezing possible in the second half of the month. The third week of September is when aspen, oak and birch begin turning on the Grand Canyon's North Rim. Layers you can shed is the standing advice.