The Arctic stratospheric polar vortex was unusually strong, cold, and long-lasting during the winter and spring of 2019-2020. This was caused by a lack of upward-moving planetary waves. The late transition of the stratosphere in spring 2020 led to warmer surface temperatures in Eurasia and North America, with some areas experiencing temperatures up to 10 degrees higher than usual. Additionally, the Arctic saw its most severe ozone depletion since 2004, with ozone levels dropping significantly below normal from March to mid-April 2020.