With temperatures soaring in many places around the United States, many might be wondering if this is a sign of another sweltering summer.
On Wednesday (March 21) alone, more than 70 major cities were within sight of record highs, according to the Weather Channel.
Quite a few of those cities have already broken the previous record high — some by a little, some by a lot.
New York City broke its record high of 68 degrees, set in 1979, by two degrees.
In Chicago, temperatures have hovered in the low to mid-80s for more than a week. On Wednesday, it reached 85. The notoriously chilly city has shattered previous record highs for the last eight days. [Weirdo Weather: 7 Rare Weather Events]
"Our records go back to 1873, so you're looking at quite a bit of time there," said Amy Seeley, a meteorologist with the National Weather Service's Chicago office.
And on Monday (March 19), in International Falls, Minn. — known as "The Nation's Icebox" and one of the coldest places on Earth — the low temperature, 60 degrees, tied with the previous record high for the day, set in 1918. (Temperatures climbed to a balmy 78 degrees.)
Forecasters say the jet stream, essentially an atmospheric fence that separates cold air from warm, is draped across the country like an S turned sideways. In the east, it's hovering above Canada, allowing hot southern air to rush northward.
When low temperatures are the same as previous record highs, "that's incredible — to me, that's just mind-boggling," said Mike Halpert, deputy director of the National Oceanic and Atmospheric Administration's Climate Prediction Center.
However, he said, it's not necessarily a harbinger of things to come. "It doesn't necessarily point to anything," Halpert told OurAmazingPlanet. "It doesn't mean it won't be a hot summer, but it doesn't mean it will be either," he said.
Halpert pointed to the freak snowstorms that hit in fall 2011, which prompted a lot of questions about whether the coming winter would be unusually cold and snowy. "Clearly, the answer was no," he said.
Yet, he said, there's a chance summer could be on the warm side. The most recent outlook for June, July and August, a big-picture projection based on large-scale climate phenomena such as La Niña, was published on March 15.
"There's a tilt in the odds toward a warmer summer for the southern two-thirds of the country, but it's not a guarantee," Halpert told OurAmazingPlanet. "We don't give guarantees in the climate business."
Reach Andrea Mustain at email@example.com. Follow her on Twitter @AndreaMustain. Follow OurAmazingPlanet for the latest in Earth science and exploration news on Twitter @OAPlanet and on Facebook.