While many remember May 2020 for the peak of the COVID-19 pandemic, the month also marked one of Malta’s most extreme spring weather events in recent memory. On 27th May 2020, the islands were hit by an unusual and highly unstable weather system that delivered nearly every atmospheric phenomenon possible – from violent thunderstorms and hail to a waterspout off Armier Bay.

The local weather page ‘It-Temp Madwarna’ looked back at this day that will go down in history for its sheer unpredictability. Despite falling well into spring, the weather that day was anything but typical for the time of year.

As described by the weather page, the instability was caused by cooler air masses in the upper atmosphere – the result of a high-pressure system over the UK – interacting with warmer air rising from the ground, particularly due to weak wind conditions locally.

Once the sun heated the ground, the rising warm air clashed with the cold air above, creating a rare level of instability for late May. Thunderclouds developed rapidly and by the afternoon, parts of the islands saw intense bursts of rain, dramatic cloud-to-ground lightning, and even large hailstones, especially around Rabat.

Perhaps most notably, a waterspout (known locally as ‘tromba’) formed off the coast of Armier, causing quite the sight, especially for May!

One very particular element of this storm is how localised it was – while areas like San Pawl il-Baħar saw nearly three inches of rainfall, others, including parts of Gozo like Għarb, remained completely dry. This is typical of such isolated convective storms, where energy is concentrated over a small area.

At the peak of the storm, temperatures in some areas dropped sharply, falling from around 23°C to just 15°C in a matter of hours!

While 27th May 2020 stands out for its intensity and variety of weather features, ‘It-Temp Madwarna’ reflected on similar localised storms have occurred in the past, particularly between April and October when ground temperatures are higher, such as those of 5th August 2018 and 24th June 2016.

These events share a few common ingredients: a mix of cool upper-level air (often from the Balkans), little to no local wind, and strong sunlight warming the ground. Gozo is typically spared the worst of such storms, as these weather systems tend to need a broader landmass to form and intensify, something central Malta provides more readily.

So if you spot such conditions brewing in the coming months, you may want to seek out some shelter!

Do you remember the dramatic May 2020 storm?