Cold air outbreaks, where cold polar air flows over warmer oceans, help restore midlatitude atmospheric temperature gradients near strong ocean currents, supporting storm formation. Using a novel method, we show that moderate outbreaks cover less than 15 % of the Gulf Stream region but explain up to 40 % of near-surface variability. In the North Pacific, they are more extensive and still account for a large share of variability, highlighting their key role in shaping storm tracks.