The hot spell experienced over the past two weeks was the longest June heatwave to hit Malta in at least a decade. 

According to the Meteorological Office, over the past 10 years there have been five heatwaves in June, including this one, with the majority lasting three days.

But this year’s – which technically ended on Thursday – started on June 20, lasting 12 days.

“This has been one of the most prolonged heatwaves to affect the Maltese islands, and has persisted for more than one week,” a spokesperson said.

June heatwaves over the past decade have occurred in 2021, 2019 (from June 8 to 10), 2017 (from June 28 to 30), 2013 (from June 20 to 22) and 2012 (from June 19 to 23).

A heatwave is defined as the daily maximum temperature exceeding the average maximum temperature of the month by 5°C or more for three or more consecutive days. This is determined using data from the climatic norm of 1981 to 2010. The standard norm for June is 28.6°C. It is 31.6°C for July.

Over the past weeks, temperatures have risen to over 40°C. June 25 was the hottest June day in nearly 100 years, with the maximum temperature reaching a scorching 41.5°C on Wednesday.

Hot, but not hot enough?

But as June gave way to July, which has a higher average temperature, the heatwave technically ended even as the temperature on Friday remained at a maximum of 35°C.

In order to continue being deemed a heatwave, the temperature would have had to reach 36.6°C, the necessary five degrees over the July average temperature.

This heatwave is the result of a persistent slack area of high pressure over the central Mediterranean, leading to very dry conditions due to hot air coming from the Sahara Desert and extending up to the south of Italy, the spokesperson said.

The high pressure has caused a temperature build-up throughout these days, resulting in a prolonged heatwave.