Running the Boston Marathon is already hard as hell ... and that's without being caught in a TORRENTIAL DOWNPOUR like the runners in Beantown are Monday!
The field of about 30,000 competitors are gonna have to be Boston Strong to make it through today's race -- attempting to run 26-plus miles through a damn flood and winds approaching 40 MPH.
Is THIS the year that an American woman captures the @bostonmarathon title for the first time since 1985? The elites are off!
Stream it here: https://t.co/3jf01x1nUc pic.twitter.com/rff1gOYIfp
Race officials also say it's the coldest marathon in 30 years ... with a starting temp of 38 degrees.
It was a pretty crazy scene at the starting line -- athletes fitted in bandanas, ponchos and trash bags -- and it's only expected to get wetter with the rain picking up in the afternoon.
Watch your steps, people.