Race coverage will be rolling along all day here and also over at SBNation Boston. Getcha popcorn-flavored gels ready.

RELEVANT: Streaming video available free here from Universal Sports HD.

Marathons and Heat: The Facts | bostonmarathon.runnersworld.com

To get an idea of today's weather, check out Amby Burfoot's rundown of what effects heat may have on runners.

Physiology vs. Psychology in Boston's Heat | Sweat Science

Beyond Burfoot's piece, check out Alex's roundup of studies on heat and athletic performance.

Record Heat Halts Chicago Marathon | WaPo online

It's never bad to look back and learn from similar races; Chicago in '07 seems like an apt comparison. It was a touch warmer in Chicago than the forecast high for today, but both temperatures are unseasonably warm (and uncomfortable!).

And don't forget: there's a post-race event sponsored by Samuel Adams at Fenway Park, which just might be the 'most Boston' thing possible that doesn't involve Ben Affleck.