Just days after much of Hungary sweltered in temperatures close to and above 40°C, parts of the country experienced an extraordinary reversal, with thermometers dropping below freezing during what has become the coldest night of the summer so far.

According to weather portal Időkép, the temperature in the Mohos Sinkhole (Mohos-töbör), a unique microclimate on the Bükk Plateau, fell to -3.8°C early on Saturday morning.

Summer frost after the heatwave

The dramatic cooling followed the passage of several cold fronts that swept across Hungary after an intense heatwave earlier this week.

While most of the country is now enjoying more comfortable summer weather, the exceptionally cold conditions in the Mohos Sinkhole produced an unusual meteorological combination: Saturday qualified as both a frost day, with a minimum temperature below 0°C, and a summer day, with daytime temperatures exceeding 25°C.

The meteorological station, operated by the Institute of Geography and Geoinformatics at the University of Miskolc, has been monitoring the unique site since 2022.

A world-famous natural “cold trap”

The Mohos Sinkhole has gained international attention in recent years thanks to its extraordinary microclimate, which regularly allows freezing temperatures to occur even in the middle of summer.

Researcher András Dobos said the latest reading represents the coldest night of this summer so far, but added that it is unlikely to remain the season’s lowest temperature, suggesting even colder mornings may still occur later in the summer.

The site has become an important international research location, with scientists comparing data from the Bükk Plateau with similar natural cold-air basins in Slovenia and the United States to better understand these rare climatic phenomena.

An extraordinary contrast

The sudden change highlights just how quickly weather conditions can shift in Hungary. Only a week ago, a third-degree heat alert was in force as temperatures approached or exceeded 40°C across much of the country.

Now, while afternoon temperatures remain pleasantly summery, some northern and northeastern regions have seen early morning lows of just 6–7°C, with the unique conditions in the Mohos Sinkhole pushing temperatures well below freezing.

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