How Will the Weather Affect the Game?
"For the next two days when the first two games of the Series are played, temperatures will be in the 40s. Here’s how the cold weather will have an effect on the game:
The flight of the baseball through the air is affected by air density. Warm and humid summer days have lower density. Colder temperatures and less humidity produce denser air, which will make it harder to hit the ball long distances; home runs will be harder to hit. A strong wind blowing away from home plate (a wind from the southwest in Fenway Park), could offset the increased density. Right now, the current forecast shows light winds out of the north and northwest for Game 1, which would not help hitting home runs. The longer range forecast for Game 2 shows moderate winds of 10 to 20 mph out of the west-southwest, which could help the hitters.
Pitchers will feel the denser air too, since the effects of spin should be stronger. Curve balls will curve more, and movement on fastballs and sliders will be greater. As a result, pitches may be harder to hit, but also harder for the pitchers to control."
-Prof. Frank Colby, Meteorology