Major League Baseball teams play 162 regular-season games. A lot of fans come through those gates, and a lot of hot dogs, peanuts and beers are sold. A massive amount of revenue comes from in-ballpark commerce, so Major League Baseball likes to keep the lights on and the games going, even through bad weather. But when the field finally becomes unplayable, the umpire can suspend play.
The Home Team and Umpiring Crew
The chief of the umpiring crew can suspend or delay play at any time, before or during the game. The home team can delay or suspend play, but must announce the decision before the game begins. The visiting team has no say and is at the mercy of their counterparts and the umpiring crew. If play is delayed in the middle of the game, a tarp is placed over the field by the grounds crew while both teams and umpires retreat to the locker rooms. The crew chief is then advised of the weather forecast and may suspend the game if he determines that conditions will not improve in a reasonable amount of time to allow completion of the game.
Official Game and Curfew
Rain delays can last hours, which wreaks havoc on pitching staffs. Each team is kept up to date on when play may resume so that each pitcher can warm-up in the bullpen. Once five complete innings have been played, the game becomes official; whichever team is leading after the fifth wins if the game is called due to weather. If the home team is leading after the visitor's have completed their half of the fifth inning, the home team is declared the winner and does not have to complete the bottom half of the fifth inning. If a game is suspended after the fifth inning and the visiting team has scored to take the lead in the top half of the inning before the home team has a chance to bat in the bottom half of the inning, the game will be suspended and completed at a later date. A game suspended before five innings are complete is determined by the umpire to be a No Game and must be replayed in its entirety at a later date. Major League Baseball does not enforce a curfew, but local and state laws might. So in some cases, a combination of time and weather may force a suspended game.