Football players have long prided themselves on braving the elements - from wearing short sleeves in frigid temperatures to completing two-a-days in the stifling heat of August.
But lightning is a whole different story.
Since the NFL adopted its current 32-team makeup for the 2002 season, Mother Nature has disrupted two preseason games with lightning.
The most recent was Saturday night, when two storm fronts swept through the Washington area and forced first a delay and then the end of the Ravens' game with the Washington Redskins.
With lightning leading officials to clear FedEx Field with 11:38 left in the third quarter, the game was called, with the Redskins, who were leading 13-7, declared the winners.
On Aug. 4, 2003, the Pro Football Hall of Fame game between the Kansas City Chiefs and Green Bay Packers was called with 5:49 left in the third quarter because of lightning. The Chiefs, who were leading 9-0, secured the victory.
The Packers were also cut short in a preseason, Hall of Fame game with the San Diego Chargers on Aug. 2, 1980, when lightning forced the game to be called with 5:29 left in the fourth quarter.
Of course, many Americans can recall commissioner Paul Tagliabue's decision to postpone games scheduled for Sept. 16 and 17, 2001, in the wake of the Sept. 11 terrorist attacks on New York City and Washington.
That move contrasted greatly with the league's decision to play games two days after the assassination of President John F. Kennedy on Nov. 22, 1963.
The Ravens were involved in a cancellation when the preseason opener against the Eagles in Philadelphia on Aug. 13, 2001, was called off because of dangerous conditions on the artificial turf.
And a 57-day players strike reduced the number of games from 16 to nine during the 1982 season.
Still, it takes a lot for the NFL to cancel a game because of weather. Although several games have been rescheduled (the Miami Dolphins have had three games moved since 2004 because of hurricanes, and the New Orleans Saints had to move a home game to Giants Stadium in New Jersey after Hurricane Katrina hit New Orleans in September 2005), no record of a regular-season game being called because of weather could be found.
And the league refused to cancel a preseason game between the visiting Dolphins and the host Saints on Sept. 3, 2004, because Miami players were concerned about Hurricane Frances, which was heading toward Florida.