Weather. Winter in Yosemite is snowy and cold, though sunny and chilly days are not uncommon. Yosemite Valley & Wawona (4,000 ft / 1,200 m): 53°F (12°C) / 28°F (-2°C) Hazy or smoky conditions may occur even during winter. In some areas, the park may have prescribed fires to mimic natural fires to promote forest health and reduce the risk of larger fires as conditions allow.