Fire crews took advantage of a dip in area temperatures to get a handle on the Robbers fire, officials said Monday.
Cooler weather decreases the intensity of the fire and reduces fatigue among the 2,200 crew members battling the 2,600-acre blaze, officials said.
The temperature in Auburn reached only 79 degrees on Monday. Today, Auburn temperatures were expected to peak at 73 degrees, according to the National Weather Service.
The Placer County blaze near Foresthill started July 11 on a blistering day with a high of 105 degrees in Sacramento.
"The higher the temperature, the lower the humidity, the more active fire and erratic fire behavior we are going to observe," said Department of Forestry and Fire Protection spokesman Daniel Berlant.
"We definitely made a lot of good progress today," Berlant said Monday evening. "That was due to the hard work of the firefighters, but with the cooperation of the weather as well."
As of 7 p.m. Monday, officials deemed the fire 45 percent contained.
"Colder weather and higher humidity helps out," said Holly Osborne, a weather service meteorologist.
Weather is a big deal in fighting wildfires: A weather service specialist is assigned to major incidents.
Fire officials aren't just keeping an eye on the mercury. They are also watching winds.
"Winds are a little stronger than they have been in the last couple of days," Osborne said.
Wind can cause hot embers to blow across cleared fire lines and spark new hot spots.
Berlant said firefighters have been using the lull in fire activity to strengthen lines at the front and back ends of the fire.
On Monday, firefighters prepared for shifting gusting winds, Berlant said. They used bulldozers to widen clearings around the fire and extinguished hot spots in charred areas. The gusty winds that crews expected did not blow, however, except for some light wind on the north side of the fire, Berlant said.
"We're optimistic that we're going to continue to make progress," he said.
Among those hoping Cal Fire will soon have the blaze under control was Mike Poulos, who with his wife has been living in a travel trailer since Wednesday's evacuation. Friday, he decided to go back to work rather than fret.
"I can't deal with not knowing what the heck to do," Poulos said Monday.
He said that on Saturday he sneaked back and didn't see any damage to his home on Yankee Jims Road. The fire-containment line, an old logging road, is less than an eighth of a mile from his home.