Heat waves: “2026 is already the year with the highest number”. How much? And when?

Portugal continental broke a new record of heat waves in 2026, according to the Portuguese Institute of the Sea and Atmosphere (IPMA). Only this year, nine heat waves were recorded. When?

In a shared note in site, the IPMA explains that a provisional balance sheet was made “which covers the period between February and October this year”. 

“ The episodes were distinguished by their duration, magnitude and territorial coverage, especially the heat wave from late June and early July, one of the most relevant since 1981”,refer.  

He adds that, “additionally, 2026 is already the year with the highest number of days of heat waves in mainland Portugal, with 98 days to date“, surpassing, for example, “the 97-day maximum, recorded in 2009, and 91, in 2017”. 

In this way, IPMA indicates that the first heat wave occurred between february 21 and 26, having occurred “in four locations of the districts of Bragança and Guarda”. 

There was another one between the days 30 march and 6 april, having affected “about 20% of weather stations”. It also points out that “between March 22 and 28 there was a heat wave very located in the region of Grande Porto”, however, for accounting purposes, IPMA considers that it is part of the second heat wave of 2026.

Days later, come in 15 and 28 april, there was the third heat wave that “covered 40% of weather stations, in the north and center, Tagus Valley and the interior of Alentejo”. “Miranda do Douro and Pinhão stood out, with durations of 13 and 12 days, respectively,” he says.

From 20 may to 1 june, a new heat wave, which began in the Alentejo and Vale do Tejo, “to the interior north and center from May 24”. “With an average duration of 9.5 days in the affected seasons, this episode was classified as the second longest in this indicator.”. 

The fifth heat wave happened between june 9 to 24, having been “registered in 14 weather stations” and covered “the interior north and center and regions south of the Tagus”. 

Come in 29 june and 1 july there was the sixth heat wave that “covered much of the continental territory and constituted one of the most relevant episodes since 1981, presenting greater magnitude and the second largest spatial extension”. 

Already in september, the eighth heat wave occurred between the days 2 and 7, having been located in the northern interior region. Later, between days 18 and 27, the heat wave “covered much of the national territory, affecting 72% of IPMA weather stations, lasting between six and ten days”. 

Finally, the new heat wave recorded between days october 10 and 16.

It should be noted that, according to the weekly forecast in IPMA, temperatures should start to drop. For this week, temperatures are not expected as high as those that have been recorded in previous weeks, predicting the IPMA that the “maximum temperature will vary between 15oC and 26oC, exceeding 20oC south of the Montejunto-Star mountain system”.