The Mets and Dodgers played each other in July, when it was hot in Los Angeles. And, by the looks of the forecast, it's going to stay hot for the first games of the National League Division Series. According to The Weather Channel, it's currently 93 degrees near Dodger Stadium, with a high of 97.
By the time the first pitch is thrown, it will have chilled to a balmy 84. It will be 87 by first pitch on Saturday evening. When they get back to Citi Field for Game 3, both teams will be experiencing a 25-degree swing—probably more, factoring in Citi Field's notorious Long Island Sound-chilled winds.
While both teams have to deal with the weather, there are a few factors to consider. First, heat tends to hinder a pitcher more than help them; they can tire more quickly when it gets hotter. The heat also gives baseballs a bit more lift, potentially turning a deep fly ball into a home run. The higher home run risk could hurt Mets starter Jacob deGrom, who has allowed 16 home runs on the year. But hot weather could possibly chase Dodgers starter Clayton Kershaw out of the game sooner rather than later, setting up a battle of the bullpens—advantage, Mets.
For the record, Kershaw has thrown more than 100 pitches in 23 of his 33 starts this season. The most pitches thrown by Kershaw was 132, in a complete-game 2-1 win over the San Francisco Giants on September 2.