The East Coast is warmer than the West Coast right now. Courtesy of NOAA It's been an incredibly weird month for weather in the US.

The East Coast is warmer than the West Coast right now. A storm that drenched California over the weekend turned an Arizona town into one of the coldest cities in the continental US. Phoenix has been colder than New York City this December, where the temperature hit a record high of 66 degrees Fahrenheit.

So what's going on?

Many of these events can be attributed to the record-breaking El Niñ0 weather pattern, which has pushed the jet stream north, allowing the East Coast to enjoy spring-like temperatures.

Here's a look at some other odd weather patterns:

Arizona hit zero degrees Fahrenheit over the weekend

A man exercises on an unseasonably warm December day in New York City. Lucas Jackson/Reuters An icy storm in northern Arizona left Bellemont, a small community west of Flagstaff, with a temperature of zero at sunrise Sunday — one of the chilliest temperatures in the lower 48 states at the time, said David Vonderheide of the National Weather Service.

The morning commute in the region Monday was slow as an initial band of snow showers neared an end and a second wave arrived. The Arizona Department of Transportation urged people to stay off major highways if possible.

Weather forecasters said wind gusts up to 40 mph would send snow swirling and further complicate travel.

Meanwhile, rain fell in central and southern Arizona, dropping temperatures in Phoenix to the mid-40s — some 10 degrees colder than New York City.

Bellemont's low temperatures were due to its location in a flat area surrounded by low hills where cold air struggles to escape, Vonderheide said. At 7,100 feet, it's slightly higher in elevation than Flagstaff.

"There are mornings every winter where Bellemont is the coldest in the lower 48," he said.

Kaitlyn Ayala (right) piles snow onto her friend, Emily Romine, on December 14, in Flagstaff, Arizona. Felicia Fonseca/AP Photo

Utah had its first major snowstorm of the winter season

The state's first major winter storm dumped a foot of snow in some parts of the Salt Lake City area, creating harrowing commutes.

Highway troopers reported more than 140 accidents and slide-offs in three northern Utah counties early Monday, but none were serious, Utah Highway Patrol Sgt. Todd Royce said.

Salt Lake City during a snow storm on December 14. Rick Bowmer/AP As much as 16 inches of snow was expected by Tuesday in some areas, National Weather Service meteorologist Christine Kruse said. Snow also fell in lighter doses in the Logan and Provo areas and as far south as Zion National Park, where the higher elevations of red rock landscapes were covered in a dusting of snow.

Many city streets were littered with cars stuck in the snow, causing backups and gridlock at some stoplights. The Hogle Zoo in Salt Lake City closed and the University of Utah in Salt Lake City canceled evening classes.

While city residents slogged their way around, ski resort officials celebrated the huge snowstorm that dumped up to a foot at many sites. "Who's excited for some Powder?" Brighton Ski Resort tweeted.

Only minor delays were reported at Salt Lake City International Airport.

The massive storm marked the latest twist in a topsy-turvy early winter in Utah that saw record high temperatures in the 60s last week.

California got covered in rain and snow

A storm that dumped rain and snow across California moved out of the soaked state Monday, leaving behind cold temperatures, powerful winds and pounding surf.

The National Weather Service said temperatures would be about 10 degrees colder than normal in Southern California and would barely top 60 during the day.

A high-surf advisory was in effect for San Diego County through Tuesday, with unpredictable waves up to 8 feet lashing the coast, accompanied by dangerous rip currents.

Drivers were urged to use caution on mountain roads, where gusts of up to 70 mph were predicted.

Higher elevations in the Sierra Nevada received 1 foot to 2 feet of snow Sunday, adding to the powder that fell last week to the delight of skiers and snowboarders.

A pedestrian gets hit by strong winds in California as a rain and snow storm moved out of the state on Monday. Nick Ut/AP

Montana and Wyoming are expected to get more than a foot of snow in the mountains

A wintry storm blowing through Montana and Wyoming was expected to dump at least a foot of snow on some lower-elevation areas and more in the mountains. Blowing snow in central and southern Montana made for treacherous driving conditions. A winter storm warning is in effect for much of the two states.