Spain is experiencing an unprecedented heatwave. In recent days, the highest temperatures of the summer so far have been recorded, a season that, far from ending, seems to be dragging on. 45,4ºC in Las Cabezas de San Juan (Seville), 42,9ºC in Xà tiva (Valencia), 39ºC in Ses Salines, Mallorca (Balearic Islands)... and so on, with 38 provinces experiencing a scorching end to summer, to say the least.
But is this really a heat wave? According to experts from the State Meteorological Agency (AEMET), a heat wave must last at least three consecutive days and be noticeable in more than 10% of cities, where the orange alert threshold must be reached, something that is happening: a total of 38 provinces are on heat alert , with temperatures ranging between 34 and 43ºC.
This heat wave is exacerbated not only by the extreme temperatures but also by the unusual time of year it has occurred. As Modesto Sánchez Barriga, spokesperson for AEMET (the Spanish State Meteorological Agency), explained, extreme temperatures have been recorded, such as 39ºC at Santiago de Compostela Airport, 42,3ºC in Cáceres, and 39,8ºC in Albacete.
The effects of this heat wave are being felt across the country, impacting public health, agriculture, and the economy. High temperatures can cause dehydration , heatstroke , and other health problems, especially among vulnerable groups such as the elderly, children, and people with pre-existing conditions. Furthermore, heat stress can negatively affect agricultural production, as some crops do not tolerate extreme heat well, potentially leading to significant economic losses . For more information on this topic, see the impacts of heat waves.
Why is this heat wave happening?
The September heat wave phenomenon may be associated with multiple climatic factors. Although there is still no consensus, experts believe that the end of the El Niño weather phenomenon is contributing to it. When El Niño ends, the atmosphere undergoes changes that promote global warming . This is because energy is released that alters air circulation, as explained by Belén RodrÃguez de Fonseca, from the Department of Geophysics and Meteorology at the Complutense University of Madrid.
When El Niño ends and gives way to La Niña , heat waves and droughts often occur in various parts of the world, including Europe. This pattern, in the context of global warming, may be one of the reasons behind the unusual heat wave we are experiencing this year. However, meteorologists caution that it is premature to draw definitive conclusions about the cause of this phenomenon. For more information on the phenomenon, see our article on how heat waves occur.
Background of heat waves in September
This is not the first year that Spain has experienced heat waves in September. In fact, historical records show that heat waves have occurred in this month in previous years. For example, in the 20th century, there were significant events in the 1970s and 80s, such as the heat wave that struck the Canary Islands from August 28 to September 10, 1976 , and another that affected the Iberian Peninsula from September 5 to 8, 1988 , where maximum temperatures of between 35 and 40°C were recorded in multiple provinces.
In 2016, an extreme heatwave occurred in early September, with Córdoba Airport recording a maximum temperature of 45,1°C , which rose to 45,4°C the following day . These types of events have been increasing, reflecting a pattern that may be attributable to climate change . According to a study by AEMET (the Spanish State Meteorological Agency), summer in Spain has lengthened by nine days per decade since the 1970s. If you would like to learn more about these phenomena, check out the article on breaking the record for heatwaves in Spain.
Expectations for September
Weather forecasts for September suggest that while some regions could experience above-average temperatures, as has been observed, other locations could experience significant drops. According to recent data, the month is expected to start with relatively unstable weather, including possible storms. However, temperatures are expected to rise again toward the end of the month, creating a turbulent landscape that could maintain extreme heat in some areas.
AEMET has also indicated drought patterns that could manifest across the country, with up to a 70% probability of temperatures exceeding the usual averages in the Iberian Peninsula and the Balearic Islands. This means that, despite the arrival of meteorological autumn, the heatwave could persist longer than expected. For more details, you can read about the heatwaves in July 2022.
On the other hand, the Copernicus analysis highlighted that September 2023 was the second warmest on record, underscoring the severity of the climate situation. Throughout September, the average surface air temperature reached 16,17°C , representing a considerable increase compared to historical levels and a clear sign of the anomalies occurring globally, which also affect Spain.
With these data in mind, it is not only important to closely monitor current weather conditions but also to implement preventive and adaptive measures to mitigate the effects of heat, especially in such dynamic contexts as those expected in the coming weeks. Awareness of the risks posed by heat waves, along with a proactive approach to public health and water management, will be key to addressing these climate challenges.
Thus, the combination of adverse weather conditions, longer summers, and the impact of climate change highlight the urgency of taking effective measures to be better prepared for future heat waves.
