Both parks closed last Thursday when smoke from the sixth-largest wildfire in recorded California history created hazardous air quality.
Park officials said air quality is projected to be in the moderate to unhealthy range for sensitive groups over the next few days.
Yosemite will reopen visitor services in stages throughout the weekend and portions of the park may intermittently close if smoke affects the air quality, park spokeswoman Jamie Richards said.
The Creek Fire, burning in the Sierra National Forest since Sept. 4, has devoured 452 square miles -- 289,695 acres -- and destroyed 855 structures, according to the California Department of Forestry and Fire Protection. It is 32% contained.
Sequoia National Park, immediately to the south of Kings Canyon, remains closed. The park is threatened by the SQF Complex of fires ignited by lightning in the Sequoia National Forest.
Burning since Aug. 19, the complex has scorched 144,708 acres -- more than 225 square miles -- of forest and was 33% contained Wednesday. The fire has destroyed 191 structures and threatens nearly 3,200 others.