Lorraine Williamson
Spain’s first official heatwave of the summer will begin on Sunday, with temperatures expected to reach or approach 42C in parts of the country.
The State Meteorological Agency, AEMET, issued a special warning on Friday afternoon for a heatwave affecting the Peninsula and Balearic Islands from Sunday 21 June until at least Wednesday 24 June.
The warning comes as Spain moves into the first weekend of summer, with residents, tourists and outdoor workers urged to take extra care during the hottest hours of the day.
Where the heatwave will hit hardest
AEMET says the episode will mainly affect the river valleys of the southwest quadrant and the Ebro, the depressions of the northeast, the eastern Cantabrian area and inland parts of the Balearic Islands.
The highest temperatures are expected in inland valley areas, where intense heat can build quickly and remain trapped through the afternoon.
On Sunday, temperatures of 38C to 40C are expected in the Ebro valley, northeastern depressions and the Tajo, Guadiana and Guadalquivir valleys. AEMET also warns that some areas could approach 42C.
In much of the rest of inland Spain and the Balearic Islands, maximum temperatures are expected to sit around 35C to 37C.
The peak could come between Monday and Wednesday
Although the heatwave begins on Sunday, the worst of the episode may not arrive immediately.
AEMET expects temperatures to rise slightly again on Monday, especially in the eastern interior of the Peninsula and in the Balearic Islands. Current forecasts suggest the episode will continue until at least Wednesday, with uncertainty over whether the heat may persist into Thursday.
That means the start of next week could bring several days of very high daytime temperatures and uncomfortable nights.
For many areas, the problem will not only be the afternoon heat. AEMET has also warned of very warm nights across wide parts of the country, making it harder for homes to cool down and increasing the strain on vulnerable people.
Warm nights
Heatwaves are more dangerous when temperatures stay high at night.
When homes, streets and buildings do not cool down properly, the body has less time to recover from the heat of the day. This can increase the risk of dehydration, heat exhaustion and heatstroke, particularly among older people, babies, young children, pregnant women and those with chronic health conditions.
Spain’s Ministry of Health says exposure to excessive temperatures can cause health problems including cramps, dehydration, heat exhaustion and heatstroke. The impact is influenced by age, underlying illness and other risk factors.
This is why official advice usually focuses not only on the maximum temperature, but also on the duration of the episode and the effect of repeated hot days and nights.
Fire risk will also increase
AEMET has also warned that the danger of wildfires will increase during the heatwave. The agency says the rise in fire risk may be accompanied by the possible occurrence of dry storms or storms with little rainfall. Dry storms can bring lightning and gusty winds without enough rain to reduce fire danger. In already dry areas, that can create difficult conditions for emergency services.
The warning comes after several weeks of high temperatures and growing concern over the start of the summer fire season. Even where there is no active red alert, people should avoid any behaviour that could start a fire, including throwing cigarette ends, using barbecues in restricted areas or leaving glass and rubbish in rural zones.
Health alerts are separate from weather warnings
Spain now works with both weather warnings and health-risk alerts.
AEMET’s weather warning system looks at expected temperatures and meteorological thresholds. Separately, the Ministry of Health’s 2026 heat plan monitors risk to health across different meteosalud zones, taking into account the impact of heat over a 72-hour period. This matters because health risk is not the same everywhere. A temperature that is dangerous in one area may be more normal in another, depending on local climate, population vulnerability and overnight conditions. Therefore check both local weather warnings and any health-risk alerts issued for their municipality or region.
What to do when it is hot
People in affected areas should avoid strenuous outdoor activity during the hottest part of the day, especially between late morning and early evening.
It is also important to drink water regularly, keep homes as cool as possible, close blinds or shutters during peak heat, and check on older relatives, neighbours or anyone living alone.
Outdoor workers, sports clubs, walkers and families planning weekend trips should also review plans carefully. The first serious heatwave of the summer often catches people out because routines have not yet fully adjusted to extreme conditions.
Elderly people, people with heart or respiratory conditions and those taking certain medication may need extra protection. Young children and pets should also be kept out of direct sun and never left in parked vehicles.
A hot start to summer in Spain
The timing is striking. The heatwave arrives just as summer officially begins, turning the first weekend of the season into a period of health, travel and fire-risk concern.
AEMET says the probability of the episode is high, although the final duration remains uncertain. The most likely scenario is that temperatures begin to fall more widely from Thursday 25 June, but the agency has not ruled out the heat continuing into that day.