Foul weather, from ice, snow and below-freezing temperatures to downpours and excessive heat, has adversely affected NFL games since the dawn of the league more than 100 years ago. But no game in NFL history matches the weird weather at the "Fog Bowl” playoff game between the Philadelphia Eagles and Chicago Bears on December 31, 1988.

Meteorologists said the fog was so thick during the game at Chicago's Soldier Field that it was like having clouds on the ground. The freak of nature was caused when cold air over Lake Michigan was blown by a breeze toward warm air at Soldier Field on the lakefront, according to the National Weather Service.

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“It will be remembered as the best game you never saw,” Fred Mitchell wrote in the first sentence of his game story in the next day’s Chicago Tribune.

The Bears won, 20-12, in the matchup that featured head coaches who despised each other: Buddy Ryan of the Eagles and "Iron Mike" Ditka of the Bears. Ryan served as Chicago's defensive coordinator on its 1985 Super Bowl championship team.

But the result of Eagles-Bears was almost secondary to the thick fog that had fans and players talking for days.

"In 30-some years of covering sports, I thought I'd seen just about everything," wrote Frank Dolson of the Philadelphia Inquirer. "Yesterday, sitting in a 50-yard-line seat at Soldier Field, I saw practically nothing."

Other NFL games have been played in pea-soup fog. Two were hosted by the Patriots at Gillette Stadium in Foxboro, Massachusetts. On January 6, 1997, New England defeated the Pittsburgh Steelers, 28-3. Twenty years later, in the Patriots’ 23-7 win over the Atlanta Falcons, the fog was so thick that NBC relied on its Skycam for most in-game coverage instead of the usual sideline cameras. (In Canada, the CFL Championship Grey Cup Game of 1962 is considered by many to be the original Fog Bowl.)

No NFL game, however, was as fogged up as the "Fog Bowl."

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“I haven’t even driven a car in anything like that before,” Chicago kicker Kevin Butler told reporters afterward.

The game started in relative comfort for fans, especially for Chicago in the wintertime, with the temperatures in the 40s, light wind and bright sunshine. Late in the first half,  the fog rolled in from Lake Michigan, enveloping the stadium in a shroud of gray.

Some believed the fog was smoke from a fire outside the stadium. Eagles wide receiver Gregg Garrity initially thought it might be snow. "I don't think a blizzard would have been this bad," he said, according to the Tribune. "You couldn't see what was going on in the backfield. It was eerie."

The fog was so thick that on-field visibility sometimes was reduced to about 20 yards. CBS, which broadcast the game on television, was forced to ground the helicopter it used for overhead shots of the stadium. The network's play-by-play broadcaster Verne Lundquist and color analyst Terry Bradshaw couldn't see the field, so they called the game from TV monitors.

Many of the 65,534 fans in attendance left their seats to watch the game on TVs in the concourse. Many others simply went home to watch.  “For fans, it’s the Invisi-Bowl,” wrote a crafty headline writer for the Tribune.

Phil Sheridan, who covered the game for the Bucks County (Pennsylvania) Courier Times, and other sportswriters were escorted from the press box to the field for a better vantage point.

"But we couldn't see the opposite sideline or either end zone from the middle of the field," he remembers. "Occasionally, players would run by, but it was impossible to know where they came from or where they disappeared to."

The Soldier Field public-address announcer, fed information via walkie-talkie from a spotter on the sideline, tried his best to provide play-by-play to in-stadium fans.

"It was like being at home and listening to the radio," said Bears linebacker Dante Jones. "You just sat there waiting for the public address announcer and the crowd. It was a totally different experience."

Sometimes fans would bizarrely cheer even a mundane play, but most had no clue what they were seeing. “It would sound like a guy was going for 1,000 yards, and he was making two,” Ryan told reporters about the fans’ reaction.

Eagles owner Norman Braman was livid the game wasn’t stopped. The NFL discussed suspending or delaying it, but referee Jim Tunney said he could see both goal posts from midfield. So, it was game on. “That ref ought to go to the Hall of Fame if he could see both goal posts,” Butler said.

The Eagles dominated, outgaining the Bears 430 yards to 341. Philadelphia, however, was mistake-prone. Before the fog rolled in, two Eagles touchdowns were called back for penalities, and tight end Keith Jackson dropped a sure touchdown pass.

The Eagles' owner suspected someone else dropped the ball.

"I think we should have had an opportunity to play this football game under reasonable circumstances, and I think those reasonable circumstances were denied us, and I am going to try to find out why," Braman said. "I think I know why."

Some speculated television dictated the game should be played despite the heavy fog.

Ryan, however, refused to blame the loss on the weird weather, although he told reporters afterward:  "...I could hardly see across the field, and I’m sure they couldn’t, either. They’d run a play, and I didn’t know who had the ball or what the hell was going on.”

At least the game gave some sportswriters a chance to flash their wit. In the next day's Tribune, columnist Bob Verdi wrote, "Could somebody have gotten hurt? Heck, somebody could have gotten lost…"

As odd as the second half was, the strangest thing was probably what followed the game. "The fog was gone," recalls Sheridan, a longtime sportswriter. "The day was again as clear and sunny as it had been before kickoff."

The next week, the Bears were figuratively in a fog, as Chicago lost to the eventual Super Bowl champion San Francisco 49ers in the NFC Championship Game.