Rapid Stratospheric Temperature Spikes Over the Arctic When temperatures in the polar stratosphere suddenly climb, climate analysts instantly recognize this as one of the most critical warning signs.

Yes, it's winter. It's been a while since we've had a cold spell of this magnitude and for this long. What's causing it?

Weather patterns like heat waves or dry spells can sometimes stall over one region. A new University of Arizona study found clues about why. The researchers analyzed tree rings from centuries-old ...