(CNN)In just a span of four states, the weather is either burning hot or freezing cold. Literally.
And it’s nowhere near winter yet.
Here’s what to expect across the country this week:
Denver could get walloped with 12 inches of snow
For the second time this month, the Mile High City is getting slammed.
The storm could leave anywhere from 6-12 inches of snow on the ground, the National Weather Service in Denver said.
The Denver area was covered with 9 inches of snow Tuesday afternoon, and Denver International Airport was blanketed with nearly 6 inches, the NWS said. The snowfall gives Denver 10.7 inches of snow for the month, making it the 14th snowiest October on record.
More snow is expected to develop Tuesday night but the intensity will gradually decrease from northwest to the southeast overnight into the morning, forecasters say.
Temperatures will plunge into the single digits and highs on Wednesday will only reach the teens, the weather service said.
Central Plains will join the winter storm ‘party’
Back-to-back storm systems will move from the Central Rockies and Plains up through the Great Lakes, the National Weather Service said.
“Some got a taste of winter last night, but all of us get to join the party tonight thru Thursday,” the NWS office in Kansas City tweeted Tuesday.
Snow and freezing drizzle will cover the area Tuesday night through Wednesday morning.
“Halloween night looks dry, but uncomfortably cold,” the forecasters said.
Midwest trick-or-treaters might get spooked by snow
The first snowfall of the season is expected for parts of the Midwest over the next few days, the National Weather Service said.
That means Iowa, southern Minnesota, northern Missouri, northern Illinois, Wisconsin and Michigan all could have a wintry Halloween.
The Windy City of Chicago could be blanketed with snow by Halloween night.
“There have been six instances in Chicago’s history where snow has fallen on Halloween, with the only date of measurable snow being on Halloween in 2014,” the National Weather Service in Chicago said.
If Chicago gets a measurable amount of snow this Halloween, it would come 17 days earlier than normal.