Azores High

The Azores High is a semi-permanent subtropical anticyclone centered over the North Atlantic Ocean near the Azores islands — a high-pressure system that dominates the climate of the eastern Atlantic, western Europe, and northwestern Africa. It is one of the two pressure centers that define the North Atlantic Oscillation (NAO), the other being the Icelandic Low. The strength and position of the Azores High determine the path of the mid-latitude jet stream, the intensity of Atlantic storm tracks, and the distribution of rainfall across Europe and the Mediterranean.

When the Azores High is strong and displaced northeastward (positive NAO phase), it steers wet, mild maritime air into northern Europe and blocks moisture from reaching the Mediterranean, producing drought conditions in Iberia and North Africa. When the High is weak and retracted southward (negative NAO phase), the jet stream meanders, cold Arctic air penetrates into Europe, and the Mediterranean receives increased winter rainfall.

The Azores High is not a stable, permanent feature. It waxes and wanes on synoptic timescales (days to weeks) and shifts position on seasonal and decadal timescales. Its variability is linked to the Arctic Oscillation, the El Niño-Southern Oscillation, and the Atlantic Multidecadal Oscillation, making it a node in the global network of coupled climate oscillations.