Although Mt. McKinley is suitable for climbing in summer, because of the extreme conditions and variable weather, the success rate in June and July is only about 50 %. All climbers must take 25 days of supplies with them when they start out, in case they are stranded by a sudden change in weather conditions.
麥肯尼峰於夏季雖然適合攀登，但受到高度和極地氣候影響，天氣詭譎多變，六、七月間登頂成功率約百分之五十，因此必須備足二十五天份的補給，以防天候突變滯留山區。