The Obama administration got off to a cold start Tuesday, but the overcast skies cleared and the sun shone down on the inaugural ceremony.
Morning temperatures were in the low 20s with a light wind and overcast skies. But readings climbed to 28 by the time of the noon ceremony.
The cold didn't challenge the record of minus 2 degrees at Ronald Reagan's second inauguration in 1985.
The normal high for Jan. 20 in Washington is 42 degrees with a low of 26.
Medical stations around the event handled 490 patients with 31 transported to hospitals. The main problems reported were falls, dehydration, hypothermia and chest pains.
Scientists studying the ice and ocean conditions off the coast of Antarctica celebrated the new administration by naming their location Ocean Station Obama, Rutgers University announced. The researchers are looking into the effect of warming on the region.
The mood was festive, but the chill was taking its toll.
Shelton Iddeen, 57, of Greensboro, N.C., huddled around the front of an ambulance to warm up.
"My hands feel really bad. You can't feel your toes," he said. "I'm more concerned about other people, the elderly and the young. I've seen a lot of people here really suffering."
Compounding the problem, warming tents and other facilities on the Mall were late opening because traffic and crowds delayed staffers from reaching them.
It was too much for Tylisa Hendrix, 18, a freshman at Alabama State University who spent the night on the National Mall, walking in socks and flip-flops. Thoroughly chilled by 7 a.m., she was heading back to her hotel to get warm.
Wearing a black coat and black sunglasses, but no hat, actress Jamie Lee Curtis danced in place on her toes to keep warm as she stood at the foot of the Capitol.
On the other hand, Nick Duny of Marshall, Alaska, was unfazed by the weather. Standing about 40 yards from the podium at the Capitol, Duny proclaimed the weather "more like spring or fall temperatures."
The worst inaugural weather day came a century ago in 1909.
President William Howard Taft took the oath of office indoors after a storm dropped 10 inches of snow over the capital city. Strong winds toppled trees and utility poles, trains were stalled and city streets clogged.
It took 6,000 men and 500 wagons to clear 58,000 tons of snow and slush from the parade route.