(CNN) -- Wait a minute, didn't spring start last week?
Folks in more than a dozen states, from Missouri to New Jersey and down to North Carolina and Tennessee, navigated dogged precipitation to get to work or school Monday morning.
Accumulations of up to 7 inches were expected in places such as St. Louis, Indianapolis and Pittsburgh. Forecasters predicted some areas would receive a foot of snow.
Mix in blustery winds, and it's a bit of a mess.
Time to break out the sleds
More than a foot of snow blanketed St. Louis on Sunday, making it the snowiest single March day ever in the Gateway City, and the second-snowiest day, no matter the month, dating back to 1892.
"I'm a little bummed out," St. Louis resident Mary Kelly said at the prospect of another snow day. "It's a little bit of a buzzkill."
Her son was excited though, getting a day off from school, with spring break scheduled to start Thursday.
"We'll break out the sleds again," she said. "We've got some pretty good sledding hills around here."
Still, the irony isn't lost on Kelly, who knows how changeable Midwestern weather can be.
"The good news is: It's St. Louis," she said. "Next weekend, it could be 80 degrees."
The snow prompted flight cancellations and delays across the Midwest and mid-Atlantic states.
Around 2 p.m. Monday, FlightAware.com said nearly 600 flights "within, into or out of the United States" had been canceled, after 415 cancellations were tallied nationwide Sunday.
The website said flights in and out of the three largest New York-New Jersey Port Authority airports -- Newark, John F. Kennedy and LaGuardia -- made up more than a quarter of those cancellations.
And even when flights weren't canceled, the storms wrought havoc on travel plans, with delays of at least an hour and a half at the Philadelphia, Newark and JFK-New York airports, and 30- to 45-minute delays at the three largest Washington, D.C., area airports.
In Indianapolis, Mayor Greg Ballard told nonessential city employees that they didn't have to come into work until 1 p.m. because of the storm, affiliate WISH-TV reported. Dozens of school districts called off classes for the day.
In several places, snow was accumulating in historic amounts.
Springfield, Illinois, witnessed an all-time single-day record of 17 inches Sunday, in a city where records go back to 1881.
In Pittsburgh, forecasters were talking about the rare, heavy spring snowfall. Up to 8 inches are expected.
"From a historical perspective, we've only had snow on the ground, this date or later, of 6 inches or more four times," Michael Fries with the National Weather Service told affiliate KDKA-TV.
The last time was in 1987, when 7.7 inches fell, setting the record for an early spring storm.
Monday's heavy snow could knock down trees and power lines.
"If you must venture out at all ... use extreme caution," the weather service warned.
Let it snow, let it snow, let it snow!
Ski areas, including West Virginia's Snowshoe Mountain Resort, 200 miles south of Pittsburgh, are hoping people venture out, and promising the "best March ski conditions in recent memory."
"Last year, we had to close by now," Snowshoe spokesman David Dekema said Monday. "By this time, we were shut down. It was warm and raining."
But this year, he said, "it's looking like winter for the foreseeable future."
Snowshoe had planned to close this Sunday, the last day of March, but the prediction of snow through Thursday is forcing a reassessment.
"We're getting a lot of feedback and questions from our guests who don't want to let winter run out here, and we're having internal discussions about what's feasible," Dekema said. "With our best final weekend snow conditions and so much terrain open, some people want to keep it going and maybe make it into April."
Deep South cold
A deep-plunging Arctic cold front is fueling the storm system, and while the Southern states didn't get much snow, they were feeling winter's bite in unseasonably low temperatures, blustery wind and overwhelming rain.
Large sections of Texas, Oklahoma, Arkansas and Louisiana shivered under freeze warnings, while temperatures in the 40s could be found in the Florida Panhandle.
Winds strong enough to prompt advisories whipped Georgia, Alabama, the Carolinas, Tennessee and Arkansas, making the unseasonably cold weather feel even worse.
And on top of that, rain deluged a wide swath of the South, with cities as far apart as Columbus, Mississippi; Birmingham, Alabama; and Charleston, South Carolina, all receiving more than 3 inches of rain -- and Valdosta, Georgia, accumulating nearly 5 inches.