Flagstaff's high elevation (2,100 metres) means it has a real four-season climate unlike any other city in Arizona. Summer (June–August) is warm and pleasant — highs around 27°C — and this is the peak season for hiking and visiting the national monuments. Afternoon thunderstorms are common in July and August (monsoon season) but usually brief.
Winter brings real snow and cold temperatures, and Arizona Snowbowl typically opens in December or January. Spring is unpredictable — snow is possible through April. Autumn (September–October) is excellent: crowds thin after Labor Day, the aspens in the high country turn gold, and the weather is clear and cool. The city's dark skies make it good for stargazing year-round.