The summer of 2026 was the third hottest recorded in mainland Portugal since 1931, new data from the Portuguese Institute of the Sea and Atmosphere (IPMA) has revealed.

Between June and August, the average temperature reached 23.17°C, which was 1.21°C higher than the average for the 1991-2020 reference period. Only the summers of 2025 and 2005 were hotter.

IPMA classified this summer as "very hot" in terms of temperature, although when it came to rainfall, the season as a whole was considered normal.

Temperatures remained generally above average throughout all three summer months, with the biggest differences recorded in June.

The heat was felt throughout the summer, with maximum temperatures averaging 30.19°C and minimum temperatures averaging 16.15°C. Both were among the highest recorded since 1931.

Two heatwaves

The summer was also marked by two significant heatwaves.

The first lasted from 9 to 24 June, while another followed shortly afterwards, between 29 June and 11 July.

The second was particularly widespread, affecting 77% of the weather stations analysed by IPMA.

During the summer, 23 new temperature extremes were recorded across mainland Portugal.

The hottest day of the season, based on the daily average of maximum and minimum temperatures across the country, was 4 July.

However, the highest individual temperature was recorded one day earlier. On 3 July, temperatures climbed to 44.3°C in Mora, in the Alentejo.

August rain changed the picture

Despite the exceptionally hot conditions, rainfall across the entire summer ended up surprisingly close to normal.

Mainland Portugal recorded a total of 43.3 millimetres of rain during the three months, equivalent to around 97% of the usual amount.

However, the rain was far from evenly spread throughout the summer.

June and July both recorded below-average rainfall, before the situation changed considerably in August.

Rainfall during August reached 260% of the normal amount for the month, helping to bring the overall summer figure much closer to average.

Much of this rain arrived towards the end of the month.

Between 23 and 28 August, heavy rain and showers affected several parts of mainland Portugal, particularly Lisbon, the Tagus Valley and the coastal area between Setúbal and Sines.

The unusual rainfall resulted in 17 new daily precipitation extremes being recorded.

The highest 24-hour total was measured in Vila Nova de Cerveira on 27 August, where 58.2 millimetres of rain fell.

The figures leave Portugal with another exceptionally warm summer in the record books. While 2026 did not overtake last year's record-breaking summer, it still ranks behind only 2025 and 2005 among the hottest summers recorded in mainland Portugal since 1931.

Set The Portugal News as your preferred source for news on Google

GoogleAdd as a preferred source on Google