The operation of retractable roofs are subject to the ground rules set by the NFL. Retractable roofs are installed in the home fields of the Cardinals, Colts, Cowboys, Falcons, and Texans. These procedures are covered in the league’s policy manuals, not in the rulebook.
Up to 90 minutes prior to kickoff, the home team must notify the referee or the designated representative from Football Operations whether the roof will be open or closed for the game. If the roof needs to be moved into that position, this must be completed before team warmups.
If the roof is open, and there is incoming hazardous weather (such as lightning or high wind), the referee will consult with Football Operations and the stadium manager about a decision to close prior to the game. If it begins raining before the game, that can be done immediately.
Changing the roof during the game
Inside 90 minutes to kickoff and during the game, the decision on the roof may not be changed except by the referee or by Football Operations.
If the game has already started, an open roof may be closed up to 5:00 of the fourth quarter if it begins to rain or if there is a threat of incoming hazardous weather. The referee makes the decision, in coordination with Football Operations, as to when the roof closes. This gives the referee the ability to factor in the current game situation and to make the transition at an equitable time, barring any emergency situation.
The game will continue to be played as the roof is closing, unless play is suspended under the usual emergency procedures.
After 5:00 of the fourth quarter and through overtime, the roof will remain open if it rains, and will only be closed if a public safety concern is involved.
Once the roof is closed, either in pregame or during the game, it cannot be reopened. No NFL game has had a reversal of the pregame roof decision, or even the possibility of doing so; more often than not, the roof will be closed if there is a forecast of bad weather.
Walls and curtains
A retractable wall is also subject to the provisions of the roof, but a decision of the wall position is independent of the roof. Retractable walls are in place at the Colts’ and Cowboys’ facilities; the large doors on the Vikings’ domed stadium that allow outside air flow are also governed by the retractable wall policy. Movable doors are a feature on the Raiders proposed stadium in Las Vegas.
If a stadium has curtains or shades to cover a glass wall, the decision must be made 90 minutes before kickoff, but there is no provision to open or close after that point. If there is sun glare during the game, the curtains must still remain in the pregame position.
For Wild Card and Divisional Playoff games, the home team is not part of the decision process, but Football Operations will refer to a team’s or stadium operator’s written policy when making a determination about the retractable features. Lucas Oil Stadium has a set policy of a game-time forecast of 40 °, wind gusts of 40 mph, or precipitation in the vicinity of the stadium as mandatory closures, or the Colts may voluntarily close for regular-season games. The Texans “consider” the decision to open the roof in a temperature range 50 °—80 ° and no significant threat of rain.
The Conference Championships and the Super Bowl are “league games” and the commissioner or his designate has the sole authority over the status of the retractable roof, wall, and curtains.
Update 1/11/2017: The original post contained the text of the league policies, and has been re-written to simplify.
Image credit: Eisenman Architects. Video credit: kevinmidtownindy