A build-up of cold air is underway across the Arctic

A build-up of cold air is underway across the Arctic as the seasonal transition to autumn accelerates, with current Ice Extent and Area above 2009 to 2018 levels.

Early September typically marks the beginning of a rapid cooling phase in the far north, driven by the sharp decline in incoming solar radiation. As the Arctic tilts away from the sun, daylight hours shorten quickly and the onset of polar night begins in the high latitudes, leaving large areas without direct sunlight for weeks.

This lack of solar heating is already evident in GFS charts, which show extensive areas of sub-zero air consolidating over Siberia and the central Arctic Ocean. The models indicate that the cooling trend will deepen in the coming weeks, laying the foundations of the polar air mass that dominates the northern hemisphere winter.