Why has this winter been so cold in the U.S. East and warm in the country’s West?

image via New Scientist

February 9, 2026, 10:20 PM

• •The eastern U.S. has experienced extreme cold due to a southward dip of the polar vortex.
• •The western U.S. has seen record warmth due to a northward bend in the jet stream.
• •The Arctic's warming may be weakening the polar vortex, making these events more common.
• •A shift in Pacific storm patterns may be causing the upcoming weather change.
• •The West faces potential drought and wildfire risks due to the warm winter.

The eastern U.S. has been experiencing a frigid winter with extreme cold, while the western region has seen record-breaking warmth, a stark contrast attributed to a persistent atmospheric pattern. This pattern is driven by the polar vortex, which, when weakened, allows cold air to dip southward, causing the eastern cold and the western warmth. The upcoming shift in weather is likely due to a change in storm patterns in the Pacific, bringing seasonal temperatures to the East and cooler, wetter weather to the West. This change, while welcome, will not erase the existing weather deficits in the West.

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