Greece is expected to experience a scorching heatwave with temperatures exceeding 40C, and in some places as reaching high as 43-44C, from Monday until at least next Friday, July 25.
In statements to the Athens-Macedonian News Agency (ANA-MPA) on Sunday, Athens National Observatory research director Kostas Lagouvardos explained that the initial wave of high temperatures started the previous week, with temperatures reaching 37C, and that the second, more intense phase will last approximately six days before a gradual cooling in some parts of Greece next Saturday.
According to Lagouvardos, the highest temperatures will be on Tuesday, Wednesday and Thursday and may even stretch into Friday, though the maximum temperatures will also depend on wind patterns. "According to the forecast data, looking at the temperature characteristics of the hot air masses we expect, in some areas we could be close to an extreme behaviour," he noted.
The highest temperatures are expected in Thessaly, parts of Central Macedonia and Thrace, as well as several parts of the Peloponnese, eastern Central Greece, including Attica.
An added challenge will be persistently high temperatures during the night, which will increase heat stress. Lagouvardos pointed out that temperatures during the previous week remained around 30C until the early hours of the morning in some areas of Attica, especially in central and southern districts.
NOA physicist-meteorologist Stravros Dafis confirmed that temperatures are expected to exceed 40C and be close to 35C even at altitudes up to 800m above sea level and climb as high as 25-26C even at altitudes greater than 1,500m in the coming week.
According to Professor Klea Katsougianni of the National and Kapodistrian University of Athens and Professor of Public Health at Imperial College London, the high temperatures could lead to greater mortality rates. "Unless we take measures to ameliorate and adapt to climate change, we will have very serious repercussions on health," she noted. 
Citing a study published in "Nature Medicine", she said that Athens was one of 10 European cities at risk of a high increase in deaths due to rising temperatures by the end of the century, unless steps were taken to contain climate change. She noted that one of the factors increasing the impact of heatwaves is their duration, which increases exponentially when this is greater than three days.