As in years past, registration for the run is done by lottery because of overwhelming interest in the race.
In a news release, race director Jim Marino said the extension came because so many potential runners have been affected by the recent winter storms.
"We are well aware that many of our participants have been dealing with major difficulties relating to the most recent weather issues causing numerous power outages in many regions of the country, especially in the Philadelphia area," Marino said.
He went on to say the extension is a "courtesy to our loyal running community" and organizes wanted to give runners "every opportunity to take part."
The Blue Cross Broad Street Run will be held May 4th.