Mother Nature put on a perfect smile for Sunday’s running of the 29th annual Kaiser Permanente Napa Valley Marathon, offering temperatures in the low 40s, overcast skies, and hardly a breath of wind at the starting line in Calistoga at 7 a. m.

Click here to see a photo slideshow from the marathon

Steve Sundell of Redwood City and Devon Crosby-Helms of San Francisco took advantage of those favorable conditions, taking off from Rosedale Road and the Silverado Trail and winning men’s and women’s overall titles for the 26.2-mile race, which is also the Road Runners Club of America National Marathon Championship.

Sundell’s time of 2 hours, 21 minutes, 3 seconds qualified him for the 2008 U.S. Olympic Marathon Trials. Crosby-Helms clocked 2:52:49 for the popular race that takes runners through St. Helena, Rutherford, Oakville, Yountville and to the finish line at Vintage High School in Napa.

For winning, Sundell and Crosby-Helms each received their weight in wine from the Silverado Trail Wineries Association, an event sponsor.

Fully paved, the USA Track & Field-certified point-to-point course challenges runners with three hills in the first six miles, but is generally considered flat to rolling the rest of the way.

“You couldn’t ask for more,” said Mary Coordt of Elk Grove, second in the women’s race. “There was a nice cloud cover just so it won’t shine in your eyes too much and a tiny breeze just to cool you off every once in a while.”

There were 1800 runners who signed up, which is 500 less than a capacity field of 2300. Race organizers blamed last year’s rainy and cold weather on the smallest field in five years.

Runners who completed the course by 12:30 p.m. — a time of 5 hours and 30 minutes — received a colorful finisher’s medal. The field was cheered by spectators, who followed the race from the adjacent crossroads on Silverado Trail and also lined the finish area.

Medical professionals were on hand to treat runners for a variety of injuries, including muscle cramping, soreness, fatigue and blisters.

“We didn’t have any major issues,” said Dave Hill, a race director. “The weather cooperated very well and it was just overall a very good day. We had a lot of people who said they’ll be back.”