It was actually too cold in Chicago to make ice Monday, NHL-caliber ice anyway.

Dan Craig and his crew of professional ice makers were ahead of schedule before an arctic cold spell hit Sunday, sending temperatures below zero overnight and halting progress on the playing surface at Wrigley Field for the Bridgestone Winter Classic 2009 between the Blackhawks and Detroit Red Wings on New Year's Day.

The optimal temperature for making a smooth, solid sheet of ice that won't chip is within 4 degrees of either side of the freezing mark.

"We have an 8-10 degree window to work in," Craig said Monday at Wrigley. "We want to make sure our official ice we want the players to play on freezes from the bottom up. If it gets too cold, it crystallizes up on top and you have no bonding to the layer below it. You have to be very patient when building a good sheet of ice."

Craig sent his crew home for the holiday with 3/4 inch of ice in place. Work will resume Dec. 26 to bring the surface to the NHL-required thickness of two inches.

The ice is scheduled to be painted white on Dec. 27. The lines and logos will be added the following day. Outdoor broadcast booths for NBC and Canadian Broadcasting Corp. have been built in the outfield.

Mayor Richard M. Daley braved Monday's chill to inspect the hockey rink at Wrigley, flanked by Alderman Tom Tunney of the 44th Ward and brass from the NHL office, Blackhawks and Cubs.

After reminiscing about what a treat it was to attend a Blackhawks game with his father when he was a boy, Mayor Daley commented on the renewed popularity of Chicago's hockey team - which leads the league in merchandise sales, according to Wirtz.

"The Chicago Blackhawks are an inspiration to everyone," Daley said. "Everyone's talking about it... The resurgence of hockey, that is the hottest ticket - not only for the upcoming New Year's (game) - but for all the Blackhawks games."