Firefighters gaining upper hand in Colorado

A fire truck is blurred in this time-exposure photograph of wildfires near Durango, Colorado, on Saturday.

LAKE GEORGE, Colorado (CNN) -- Firefighters said Sunday they were "on the downside" of a massive Colorado wildfire that threatened Denver suburbs in its early days and has cost more than $21 million to battle.

With the help of three consecutive days of favorable weather, teams had two-thirds of the 137,000-acre Hayman fire contained Sunday, officials said, adding that another day of good conditions could make the difference.

"Things are looking really good," said fire information officer Chris Walker. "[Sunday] is a bit of a test day. Relative humidities are dropping, and hopefully that'll bring up any spots we've missed so we can nail those down.

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"There's not a lot of flame out there," he said. "There are some hot spots, which can be anywhere from a tenth of an acre to 10 acres, and they're out there isolating those spots and taking care of them now."

The Hayman fire began June 8 and quickly spread north toward Denver's southern suburbs. But the wind turned, and more than 2,500 firefighters kept the flames contained largely to the Pike National Forest.

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The fire has burned 114 homes, officials said. Some evacuated residents have been allowed to return with a warning to be ready to move out again if conditions warrant; more than 2,000 people remain evacuated.

The fight with the Hayman fire has cost an estimated $21.7 million, officials said.

Elsewhere in Colorado, the 63,466-acre Missionary Ridge fire near Durango was 30 percent contained, and some evacuated residents were allowed to return to their homes.

The 8,150-acre Million fire in Rio Grande National Forest was 50 percent contained. The 12,209-acre Coal Seam fire, which at one point forced the closure of Interstate 70 about 160 miles west of Denver, was 90 percent contained.

-- CNN Correspondent Mark Potter contributed to this report.