Summer 2025 is on track to be one of the two hottest ever recorded in Spain, nearly matching 2022.
A historic August heatwave set a new record for intensity, with a temperature anomaly of 4.6°C, according to the national meteorological agency AEMET.
Based on observed data and forecasts through 31 August, summer 2025 is almost certain to be one of the two hottest summers on record. It is nearly tied with summer 2022, currently the warmest on record, and both clearly surpass the historic summer of 2003.
During 2025, warm spells have vastly outnumbered cold ones. While March was notably cold and May was close to average, all other months have been warm, very warm, or extremely warm.
As a result, 2025 ranks as the second warmest year on record from January to August, just behind 2024, in what is effectively a four-way tie among the past four years, all well ahead of previous years in the historical record.
This summer’s temperature pattern has been marked by a prolonged period of above-average heat in June and early July, a cooler spell at the end of July, and then the most intense heatwave ever recorded in Spain, which hit in August.
The most intense heatwave in history
The recent August heatwave was the most intense ever recorded in Spain, exceeding the 2022 event with a temperature anomaly of 4.6°C, according to provisional data from AEMET. It surpasses the previous record set in July 2022, which had an anomaly of 4.5°C.
The heatwave lasted sixteen days, making the first twenty days of August the warmest such period (1–20 August) in Spain since at least 1961. More specifically, the stretch from 8 to 17 August was the hottest ten-day period ever recorded in the country, dating back to at least 1950.
The scale of this event becomes clear when looking at historical data: five of the 20 warmest periods on record are from the recent heatwave, and 15 have occurred since 2022. Based on observed data and forecasts through 31 August, this month is likely to rank among the four warmest Augusts in the historical series. This continues a pattern in which four of the five hottest Augusts have taken place within the past four years.
"The persistence of extreme heat intensifies its adversity," AEMET emphasised in a post on social media. "The health of vulnerable people suffers, and the level of fire danger increases".
Following the end of the heat wave on 18 August, Spain has seen a period of cooler-than-normal temperatures for the season. However, temperatures are expected to rise again in the coming days, with a possible further drop before the end of the month.
Climate change as a root cause
The average temperature in Spain has risen by 1.69°C between 1961 and 2024, leading to more frequent episodes of above-normal temperatures. When these occur in summer, they often result in longer and more intense heatwaves.
Scientific evidence shows that heatwaves in Spain are becoming longer, more widespread, and stronger. Although the county has always experienced hot summers, recent years have seen more frequent episodes of very high daytime and nighttime temperatures.
Climate change is driving this rise in temperatures and the increasing occurrence of extreme heat events, as confirmed by the IPCC’s analysis of global temperature trends.
Climate projections suggest that by the middle of the 21st century, typical summers in the Mediterranean region, including Spain, could be around 2°C warmer than between 1981 and 2020. Alarmingly, the summers of 2022 and 2025 are already comparable to those expected in mid-century conditions.
The fact that four of the five most intense heatwaves have taken place since 2019 is no coincidence. While not every summer will be hotter than the last, the overall trend towards more extreme summers is clear and undeniable.
In light of this reality, the focus must be on both adapting to and mitigating climate change, recognising that today’s summers are warmer than those of past decades, even though very hot summers have also occurred in earlier years.
