By Brian Burke
A few years ago I looked at how dome teams tend to struggle in cold weather. I wanted to know if dome team underperformance in the cold was indeed true and if so how big was the effect. The answers were: Yes and huge. Last season I redid things using actual game temperatures and found just as big an effect.
With the weather as it is on the east coast today, I looked at this phenomenon once again. We have two more years worth of data thanks to the addition of 1999. Plus, I was able to reconstruct nearly another half season worth of data by replacing missing game temperatures from the gamebooks. I also broke out teams that played in retractable-roof stadiums by season.
Here are the results if we count retractable teams as dome teams. There's a case to be made that retractable home environments are closer to dome environments than open air stadiums. The chart below plots road team winning percentage according to game temperature.
Keep in mind sample sizes become small at temperature extremes. The key observation is not that dome teams lose in the cold, but that they lose more often in the cold than they do in moderate temperatures. You can see that visiting dome teams win nearly as often as their open-air counterparts do when the temperature is mild or warm.
Here are the results if we separate dome teams, retractable teams, and open air visitors. The sample sizes get even smaller at the extremes, particularly for the dome/retractable categories. For example, there are only 4 cases of retractable-roof teams playing in the 19-28 degree temperature bin.