General Hitchcock Highway opened before noon Friday, but only to motorists with 4X4 vehicles, all-wheel drive or tire chains.
Snow and ice remain a concern on the highway that leads to Mount Lemmon.
A storm moved into Tucson overnight bringing wind and rain to the valley.
At least five inches of snow had fallen on Mount Lemmon by early Friday morning, though more was expected.
Higher elevations across southeastern Arizona are under a winter weather advisory until 11 p.m. Friday, the National Weather Service in Tucson said.
