Snow fell on the peak of Pelister, at 2,601 metres above sea level. In the middle of July. The Pelister National Park confirmed that changeable weather and low temperatures turned the rain into snow.

The photograph comes from staff at the national broadcaster's station on the summit. The park says that Pelister, as the king of Macedonia's mountains, remains unpredictable and powerful. Snow during the summer months on the highest parts of Pelister is nothing new - conditions at that altitude shift abruptly even in the hottest months.

The numbers from Bitola show the difference better than any description. The previous day at 17:00, the reading was 26 degrees. The next day at the same hour - just 12 degrees, with the temperature still falling. Half the heat vanished in 24 hours.

The same thing happened on Musala, the highest peak in the Balkans. The upper reaches of Rila turned white with light snow, and Bulgaria's weather services issued a yellow warning for thunderstorms across 10 regions. At 1,200 metres the maximum was around 13 degrees, at 2,000 metres around 8, and on the highest parts temperatures dropped to near zero.

So in the same week when people down below are hunting for shade and air conditioning, snow is falling on two Balkan peaks and a north wind is blowing. That is not proof for or against anything - mountain weather has always been its own master. But it is a good reminder of how narrow the line is between a summer day and a winter scene in the Balkans, and how easily it gets underestimated when somebody heads up a mountain in short sleeves.

If you have a trip to Pelister or Rila planned in the coming days, check the forecast twice. The drop from 26 to 12 degrees does not feel the same at 2,601 metres as it does in Bitola.