Home runs in Anaheim: nighttime, anytime, it's alright

Baseball analysts on television are a funny breed. They mix stats and narrative to help package a product, to provide insight on what is happening in the field of play. Recently, the Blue Jays were in Anaheim to play the Los Angeles Angels of Anaheim at Angel Stadium of Anaheim while Anaheim peppers were being grown miles away in New Mexico.

During a night game, Edwin Encarnacion flied out to center field which caused Gregg Zaun, former Blue Jays catcher and current Rogers Sportsnet analyst, to reason that it would have been a home run had it not been for the 'marine layer'. He purported that a layer of air forms in the Los Angeles area at night which keeps the ball down, turning extra base hits into easy outs. I had heard this theory before, but never in such detail. After a cursory glance at the Wikipedia entry on the marine layer, I was led to believe that the phenomenon would be dispersed by the heat of the sun, and there would be more of an effect on home runs hit in day games, while the dense layer of air was still hanging around.

I didn't take Zaun for much of a meteorologist, and for my first foray into baseball spreadsheetery (a term I just coined), I wanted to prove him wrong. I pored over game logs for Angel Stadium of Anaheim from 2002 to 2011. For my theory to be correct, there would have to be more home runs hit during night games, and for Zaun to be the next Harold Hosein, the opposite would have to be true. Here are the findings:

Year	HR/Day	HR/Night
2002	2.09	1.69
2003	1.95	1.82
2004	2.17	2.10
2005	2.17	1.68
2006	2.04	1.62
2007	1.30	1.71
2008	2.36	1.73
2009	2.43	2.38
2010	1.68	1.69
2011	1.44	1.67

As you can see, with the exception of 2007, 2011 and by the slightest of margins 2010 - Zaun was right. There is a definite decrease in number of home runs hit in night games compared to day games. It should be noted that over the ten-year span, there were fewer home runs hit in Angel Stadium (1495) than in games played by the Angels on the road (1666).

Stupid numbers not backing up crazy theory I had about a ballpark a week and a half ago...

— brendan mcknight (@toysubmarine) May 15, 2012

...at least I now have a somewhat comprehensive workbook on home runs hit at Angel Stadium of Anaheim from 2002 to 2011.

— brendan mcknight (@toysubmarine) May 15, 2012

That's one instance of an analyst that's not completely off the mark when it comes to facts and narrative. Now if we could only get Buck Martinez to stop calling Ben Francisco a 'veteran'.