Yukon-Charley Rivers covers 2.5 million acres in eastern Interior Alaska. It is flanked to the north and northwest by the Brooks Range and to the southwest by the Alaska Range. The climate of the interior area between these two mountain ranges is generally classified as sub-arctic, with exceptionally cold winters, relatively warm summers, low annual precipitation, and generally high winds.
The elevational range of the preserve (600 to 6,000+ feet) produces local variations in weather and climate. Above timberline, at about 3,000 to 3,500 feet, the climate is generally classified as arctic with cooler summers, warmer winters (due to prevailing cold air inversions), heavier precipitation and increased winds, compared to the sub-arctic landscape below and within timberline.
Autumn: The transition from summer to winter is rapid. Peak fall colors occur in the high country in late August and by mid September, most aspens and birches have turned golden. Ice begins flowing in the Yukon River in late October, with freeze-up usually by mid-November.