Spain’s first summer heatwave is set to last at least through Wednesday

Spain is heading into its first official summer heatwave of 2026 after the state weather agency AEMET activated a special warning on Friday, June 19.

The episode is expected to begin on Sunday, June 21, and last at least through Wednesday, June 24. AEMET’s outlook points to the hottest stretch running from Sunday through Wednesday, with the possibility that the heat could extend into Thursday.

The warning comes in the first days of astronomical summer and covers a wide area of the country. Forecasts point to intense daytime heat, unusually warm nights and a rising public-health risk for people most exposed to high temperatures.

Timing of the heatwave

Reporting in EL PAÍS said AEMET has timed the event to start on Sunday and continue through at least Wednesday. Cadena SER reported that the hottest conditions may arrive on Sunday and again on Tuesday, before a possible easing from Thursday as a DANA approaches.

That leaves the back end of the episode slightly uncertain, but the core timing is now clear. The agency’s current guidance points to several consecutive days of extreme heat rather than a short-lived spike.

AEMET had already been warning on June 17 that Spain was likely heading toward its first summer heatwave. By June 19, that forecast had turned into a formal special alert.

Where the heat will hit hardest

The highest temperatures are expected in the Ebro valley and other northeastern depressions, where readings could reach 38C to 40C. In parts of the Tajo, Guadiana and Guadalquivir valleys, the forecast rises to around 42C.

Some later coverage pushed the top end slightly higher in isolated spots, with reports citing temperatures up to 44C or even close to 45C. The most consistent official message across the coverage is that inland valleys in central and southern Spain face the greatest risk of extreme heat.

The more exposed zones also include the interior of the Balearic Islands and the eastern Cantabrian area. AEMET says many places will also see very warm nights, which matters because overnight cooling is limited and the body has less time to recover from daytime heat.

Why the warning matters

The strongest health risks fall on older adults, children and people with chronic conditions. Persistent heat can become dangerous quickly when it is paired with warm nights, because the body never gets a full break from heat stress.

AEMET and the reporting around its warning also highlight wildfire danger. Persistent heat and dry thunderstorms can raise the risk of ignition and make emergency response more difficult if fires start.

That combination of heat, dry conditions and warm nights is why local authorities may need to adjust public guidance, outdoor work schedules and emergency preparedness even before any new restrictions are announced.

What has changed since the first warnings

The sequence began on June 17, when AEMET was already warning that Spain was likely to face its first summer heatwave. Two days later, the agency moved from general expectation to a more specific special warning.

EL PAÍS reported that the alert begins on Sunday, June 21, and lasts at least until Wednesday, June 24. Cadena SER added that the most intense conditions may cluster around Sunday and Tuesday, with Thursday bringing a likely temperature drop if the current outlook holds.

AS said the heatwave could extend through Thursday, while also echoing official advice on how to cope with the heat. The differing reports do not contradict the main forecast; they mainly reflect uncertainty about how long the event will fully satisfy heatwave criteria.

Public-health and fire implications

The stakes are clearest for people most vulnerable to heat-related illness. Those include older adults, young children and people living with chronic conditions, especially if they are exposed outdoors or in poorly cooled housing.

Warm nights make the episode more stressful than a one-day spike in daytime temperatures. When overnight temperatures stay high, recovery becomes harder and the health burden can build day after day.

The wildfire risk matters for the same reason. Heat that persists across several days can dry out vegetation and, when combined with dry thunderstorms, create conditions in which fires can start and spread more easily.

What to watch next

The main question now is whether AEMET extends the warning beyond Wednesday into Thursday. The agency’s current language leaves that door open, even as it suggests a broader temperature drop is the more likely outcome later in the week.

The next developments to watch are updated regional heat or fire alerts, any new health guidance from Spain’s Ministry of Health and regional authorities, and the first confirmed temperature readings once the heatwave begins on Sunday.

Authorities will also be watching for any knock-on effects on outdoor work, transport and wildfire preparedness if temperatures reach the forecast range in the interior valleys.

For now, Spain’s first official summer heatwave of the season is no longer just a forecast. It is timed, mapped and publicly warned, with the hottest stretch expected from Sunday through Wednesday and a chance that the event lasts longer.