Unusual and Record-Breaking Cold Spell in South America 

On 30 June, both Chile and Argentina ranked among the coldest places on Earth, excluding the polar regions.

It was due to the persistence of a powerful polar-origin anticyclone which extended into parts of Paraguay and Uruguay, causing unusually low temperatures for the season.

Although the Andean mountains and Patagonia are no strangers to cold temperatures in winter, the severity of this event was exceptional and even affected low-lying areas.  Between 26 until the peak on 30 June, the cold air mass affected the southern part of the continent.

According to reports from the Chilean Meteorological Directorate (DMC) and Argentina’s National Meteorological Service (SMN), numerous weather stations set new temperature records, with some falling below -15 °C, particularly in Patagonia, the Andes, and inland continental areas.

The cold spell also impacted agriculture, with preliminary reports of damage to sensitive crops in agricultural valleys of central Chile and northern Patagonia, where early frost could affect fruit and winter crop production.

Snowfall in towns which are not used to receiving snow also disrupted transport and education.

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Chile declared a Preventive Early Warning in worst affected areas. Thanks to accurate forecasts and early warnings, no casualties were reported.

However, cold and stagnant air caused a buildup of pollutants and poor air quality in several central Chilean cities—such as Santiago, Rancagua, and Talca.

On 26 June 2025, a rare snowfall event affected the arid expanse of the Atacama Desert, known as the driest place on Earth.

The snow covered the Operations Support Centre of the ALMA Observatory in Chile, situated at an altitude of 2,900 metres. Snowfall in this location is highly uncommon, with the last significant event occurring over a decade ago.

New records of low temperatures included:

• Temuco: -7.9 °C
• Puerto Montt: -8.1 °C
• Chillán: -9.3 °C

In Argentina, the polar cold wave severely affected much of the southern and central regions, with temperatures between 10 and 15 °C below the seasonal average.

• Yellow alerts for low temperatures were issued in provinces such as Buenos Aires, Córdoba, and Santa Fe.
• In Chubut and Neuquén, extreme lows near or below -9 °C were recorded.
• In Patagonia and the Cuyo region, temperatures hovered around -16 °C.

Snowfall occurred in unusual locations, such as Mar del Plata, the Calamuchita Valley in Córdoba, and hilly areas of northern Patagonia.

The presence of this cold high-pressure system brought marked atmospheric stability, which contributed to clear skies and intense frost.

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*SOURCE: The World Meteorological Organization. Go to ORIGINAL: https://wmo.int/media/news/southern-south-america-hit-exceptional-cold-spell 2025 Human Wrongs Watch