Roses in the rain? New Year's Day parade in Pasadena gets wet forecast. Bundle up for NYC ball drop

For the first time in 20 years, rain is expected to intrude on the Rose Parade in Southern California, a venerable New Year's Day event that attracts thousands of spectators and is watched by millions more on TV.

Storms caused Christmas week flooding, mudslides and other miseries across the region. Now comes a 100% chance of rain Thursday in Pasadena, the National Weather Service said.

“We try not to say that word around here,” joked Candy Carlson, a spokesperson for the Pasadena Tournament of Roses, the organization behind the 137th Rose Parade, which precedes the Rose Bowl College Football Playoff game.

Arctic air is meanwhile expected to blanket much of the eastern two-thirds of the country, the weather service said.

In New York City, forecasters predict temperatures in the low 30s Fahrenheit (around zero degrees Celsius), which is not unusual, when the ball drops in Times Square on New Year’s Eve. Light rain is possible in Las Vegas, where several casinos will be shooting fireworks from rooftops.

During Nashville's Big Bash, a New Year's Eve event at a park, temperatures will be in the low 30s when an illuminated music note drops at midnight in the Tennessee city. New Orleans will be in the mid-40s Fahrenheit (around 7 degrees Celsius) for a free concert and fireworks along the Mississippi River.

At the Rose Parade, it has rained only 10 times in the parade's history — and not since 2006, Carlson said.

Rare wet weather is unlikely to keep floats, marching bands, entertainers and others from participating. Carlson said people riding on floats will have rain gear if necessary, and tow trucks will be standing by in case of mechanical problems.

Spectators will need to prepare, too. Umbrellas are not allowed in parade seating areas that require tickets, though the ban doesn't cover people who simply line up along the nearly 6-mile (10-kilometer) route. Curbside camping — no tents — begins at noon Wednesday. Rain also is predicted that day.

“Last year's parade theme was ‘Best Day Ever!’ and six days later it was the worst," said Lisa Derderian, spokesperson for the city of Pasadena, referring to the devastating Eaton wildfire in Los Angeles County. “We want to start the new year on a high note. Hopefully Mother Nature cooperates with the weather.”