It may be May 1^st, but in the front range of the Rocky Mountains it's still winter. The Rockies are expected to get 5 inches or more of snow, from parts of Colorado to Wyoming. Drifting snow is making travel difficult in southeastern Wyoming, but will have little impact on Denver's airport.

Much of the snow will quickly turn into slush, due to high temperatures in the 70s. These temperature swings - from wearing shorts and T-shirts to winter jackets in a few short days - are a nightmare for people running nurseries in the northeast. Many will have to bring plants in and out of greenhouses every few days for the next few weeks.

"Crazy temperature contrast," said meteorologist Kathy Sabine at CNN affiliate KUSA.

"It's incredibly frustrating," Trela Phelps, manger of City Flora, told affiliate KDVR. "We keep going back and forth all the time, and now Jack Frost is visiting us once again." 

The Colorado Department of Transportation is prepared for the late snow, with almost 80 plows clearing roadways. The average date for the last snow of the season in Denver is April 26, but the record for the latest snowfall ever was June 12, 1947, according to the National Weather Service. Nevertheless, the early May snow will be historic across portions of the Midwest.

Many residents are used to such weather changes. "You know, that's Colorado for you," a young man told KDVR. "Not much you can do about it, you just got to sit back and just kind of take it as it comes."

On the bright side, the storm could bring up to 20 inches to the northern Colorado mountains, which will be a late boost to the snowpack that provides the state's water supply.

In contrast, residents of Phoenix are braving triple-digit temperatures until Wednesday. The heat wave will last another day across New Mexico and western Texas. However, then daytime highs will drop to the 50s on Thursday.