The South Rim is 7000 feet above sea level, which means snow in winter and cool nights even in summer. Inner canyon hiking (below the rim) is another story, however: summer temperatures along the Colorado River at the canyon bottom can reach 120º F. The North Rim is 8000 feet above sea level and can receive snow throughout most of the year. Weather is particularly changeable in spring and fall; visitors should be prepared for a variety of climates.

The high altitude of both the South and North Rims may cause visitors with respiratory or heart problems to experience difficulties. All walking at this elevation can be strenuous.