July 19, 2025 – While much of the Northern Hemisphere swelters under relentless heatwaves, a starkly different scene is unfolding across parts of South America. Chile and Argentina, in particular, have been gripped by an extraordinary cold wave, driven by a rare and potent polar anticyclone that has sent temperatures plummeting as low as -15° Celsius (5° Fahrenheit) in some regions.
This unusual winter phenomenon has transformed landscapes, disrupted daily life, and raised questions about the increasingly unpredictable nature of global weather patterns.
The Anatomy of a Deep Freeze
At the heart of this frigid assault is a polar anticyclone – a high-pressure system born from the Earth’s poles, characterized by masses of cold, dense, sinking air. While winter in the mountainous and southern reaches of Chile and Argentina typically brings cold, the intensity and widespread impact of this particular anticyclone have been exceptional. This powerful high-pressure system has ushered in stable atmospheric conditions, leading to clear, frosty skies and severe temperature drops, especially during the long Southern Hemisphere nights.
Records have shattered across both nations. Chilean cities like Temuco and Chillán have registered their lowest temperatures in decades, while vast swathes of central and southern Argentina have experienced temperatures a staggering 10-15°C below seasonal averages.