"I don't think it's going to be a soaker that is going to put it completely out," Kyle Fredin, meteorologist for the National Weather Service in Boulder, said Saturday. "I don't think it will be a significant rain storm."
Fredin said there was a 30 percent chance of rain for Larimer County, The Denver Post reported.
Firefighters said they they sent out 860 evacuation phone calls Friday due to 45 mph winds, the Post reported.
The Poudre Fire Authority in Fort Collins, Colo., said 579 of the notices remained in place overnight.
"Winds have been extremely erratic," said Capt. Patrick Love, a Poudre Fire Authority spokesman.
Authorities said they were worried the fire might start to move south, toward open ground and homes.
About 50 homes are threatened by the fire, the newspaper said.