As temperatures are expected to hit and even exceed 40 degrees Celsius in many parts of the country this weekend, a National Observatory of Athens (NOA) scientist said Greece may be in for the hottest May heatwave in at least 50 years.

Speaking to state broadcaster ERT on Friday, University of Crete Professor Nikos Michalopoulos, who is also head of the NOA’s Institute for Research and Sustainable Development, said that the last time Greece saw temperatures reach the 40C mark at this time of year was in 2017, when the Peloponnesian city of Argos hit 40.2 Celsius on May 13, and in 1969, when the daytime high in the central Greek city of Larissa reached exactly 40 Celsius on May 30. Lamia came close with 39.6 degrees Celsius on May 23, 1973, and Hania in Crete with 39C on May 25, 1994.

Michalopoulos said that while warm weather is not unusual in May, temperatures above 35 Celsius, and especially in the middle of the month, are quite rare. He also said that if forecasts for temperatures as high as 41 Celsius this weekend are proven correct, Greece may experience the worst mid-May heatwave on record in 150 years.

The NOA, he said, has the oldest weather station in Greece at its historic facility in the central Athens district of Thiseio, where “data for the last 150 years… show that the highest temperatures during May were recorded in the last 10 days of the month and never surpassed 37 degrees Celsius.”