Boston Marathon runners are off

The men are off at the Boston Marathon.

Defending champion Wesley Korir was among those leaving Hopkinton at 10 a.m. Just behind the elite men was the remainder of a field of 27,000 on its way for the 26.2-mile trek to Boston's Back Bay.

Americans Shalane Flanagan and Kara Goucher left about 30 minutes earlier, hoping be the first U.S. winner at the world's oldest annual marathon since 1985.

The temperature was 48 degrees with a few clouds in the sky, perfect conditions for the 117th running of the race. Temperatures were expected to reach the mid-50s.

That's a lot different than last year, when temperatures spiked toward 90 and organizers offered an unprecedented deferment into the 2013 race.