Smoke from the fire is heaviest during morning hours, but as temperatures rise in the afternoon, the Wasatch Back should see improved conditions.
Health officials said sensitive groups should use caution or remain indoors when drift smoke is present.
The human-caused fire, which started more than a week ago, is 10% contained.
Fire officials said decreased winds should help after the fire grew rapidly over the weekend with high winds and unseasonably warm and dry conditions.
Fire crews are attacking the blaze with aerial retardant drops and may start using dozers to create fire lines on the fire’s eastern perimeter.
Evacuation orders for the North and West Forks of the Duchesne River remain in effect.
The Granddaddy Lakes area of Ashley National Forest and the town of Hanna in Duchesne County are under a “ready” order, meaning residents should have bags packed and be ready to leave on notice.
Portions of the Uinta-Wasatch-Cache and Ashley National Forests affected by the fire are closed. Highway 35 will remain closed until fire activity decreases and the road can be cleared of debris.