Citizens Bank Park blows.

Bandbox. Launching pad. A joke. That’s how people describe Citizens Bank Park. And for good reason. It is really, really easy to him homers in Philly.

How easy?

ESPN keeps a stat called “park factor”, which compares teams’ rate of stats at home vs. the rate of stats on the road. A rate higher than 1.000 favors the hitter. Below 1.000 favors the pitcher. Citzens Bank Park has a rate of 1.395 for homers — the highest of all the MLB stadiums. That’s higher than Coors Field AND the Great America Ballpark in Cincinnati.

The prevailing wisdom is that the fences at Citizens Bank Park are too close. But the stadium has almost the same demensions as Veterans Stadium. So it can’t be that. Plus,before the 2006 season, the Phillies moved the left-field fence back five feet, just for good measure. And it hasn’t made much of a difference.

Until recently, we haven’t had any idea why homers are so common at the new Philadelphia baseball venue.

But now along comes Philadelphia Inquirer weather blogger Tony Wood, who says he has done some research and has concluded that it’s not the short fences that are helping the baseballs leave the yard in a hurry. It’s the wind.

From the Philadelphia Inquirer:

Here’s why: In contrast to hulking Veterans Stadium, winds pour through Citizens Bank Park like water through a flow-through tea bag. Balls that get airborne are lifted up, up and away.

The most obvious suspects are the prevailing southwest and south winds of summer, which blow straight out to center and right-center fields. Those winds increase with height. Other factors might also be at work.

What is clear is that the atmospheric environment in the new park is utterly different from that of its predecessor, even though it is across the street from the old park.

Phillies president Dave Montgomery says that “the structural mass of Veterans Stadium – totally enclosed save for the exit-ramp openings – had a blocking effect on the movement of air” and Jim Eberwine, a meteorologist at the National Weather Service in Mount Holly, agrees.

Other reasons the Shitizen might be prone to more home runs: a heat island effect, the big gap in left-center, and strong winds originating from the confluence of the Delaware River and the Schuylkill.

Or it could just be that Ryan Howard is a super-freak home run hitting behemoth.