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Heatwave in Basque Country

Maximum temperature, NWS heat index, humidex and 7-day forecast for Vitoria-Gasteiz and the rest of Basque Country. AEMET regional record: 42.0 °C (Bilbao, August 2003).

Heat index in Vitoria-Gasteiz
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Current T / Humidity

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Open-Meteo real-time data.

Humidex

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Canadian index.

7-day forecast for Vitoria-Gasteiz - days with feels-like >35 °C

DayT maxFeels-like maxOver threshold
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Forecast highs map for Basque Country

Real-time Open-Meteo data.

Cooling shelters in Basque Country

Official AEMET warnings

Extreme heat in Basque Country

Basque Country is one of the Spanish regions where summer heat reaches critical levels during June, July and August. The official AEMET record for the region is 42.0 °C (Bilbao, August 2003). The number of days above 35 °C has increased measurably over the past two decades, partly due to global warming and partly to the urban heat island effect in major cities.

The feels-like temperature, computed with the NWS Heat Index or the Canadian Humidex, typically exceeds the dry-bulb value by 3-8 degrees when humidity rises above 50%. In coastal areas this is the norm; inland, the most dangerous factor is persistent tropical nights (above 20 °C) that prevent physiological recovery.

Health and cooling centres

People over 65, those with chronic cardiac or respiratory conditions, pregnant women and small children are the most vulnerable groups. Use municipal cooling centres (libraries, community centres, air-conditioned shopping malls) during the central hours of the day. Stay hydrated and watch for headaches, nausea and absent sweating. Dial 112 for any suspected heat stroke anywhere in Basque Country.

How to read the data

The 7-day forecast box shows expected highs and maximum feels-like temperatures for Vitoria-Gasteiz. A run of more than 5 days with feels-like values above 35 °C is flagged as a probable heatwave, based on our simplified version of the AEMET rule (3 days above the 95th percentile of historical summer highs). The map shows current-day highs for Basque Country. Check official AEMET warnings at aemet.es.

Heat in the Basque Country, with thirty years of data

In the Basque Country heat is a matter of a southerly wind. With a southeasterly flow the air descends overheated from the plateau and Bilbao or San Sebastián can pass 38 degrees with the Bay of Biscay at twenty. These are the days of greatest contrast in Spain: forty kilometres inland and fifteen degrees of difference from the north-facing coast.

How hot it really gets here

35 °C does not mean the same thing in Córdoba as in Santander, so a fixed number is the wrong place to start. Taking Vitoria as the reference point, the extreme-heat threshold specific to this place — the 95th percentile of July and August maxima, which is the criterion AEMET uses — sits at 33.2 °C, in the middle of the national range. It is exceeded on about 4 days a year.

In absolute terms that is 1 days a year at 35 °C or above and 0.0 at 40 °C or above, with a mean August maximum of 24.7 °C. The nights count as much as the days: there are 0 nights a year when the temperature does not drop below 20 °C, though 25 is virtually never held.

Is it getting worse?

That is the question that matters most, and the series answers it on its own. In Vitoria, days above that 33.2 °C threshold went from 2.4 a year on average in 1995-2004 to 5.9 in 2015-2024. The gap is large and points one way only: 4 more days a year above the threshold, 146 % more than thirty years ago. Nights that do not drop below 20 °C have made the same journey: from 0 to 1 a year.

What counts as a heatwave here

There is no universal number: 35 °C is an anomaly in Santander and an ordinary July afternoon in Córdoba. So the definition is built from each place’s own record. Applying AEMET’s criterion — three consecutive days above the 95th percentile of July and August maxima — that threshold in Vitoria stands at 33.2 °C, and across 30 years of record 11 episodes have occurred. The longest ran 7 days in a row. The hottest day in the whole series was 9 August 2023, at 39.0 °C.

Which months bite

The bulk falls in August, but the spread says more than the total: where the season stretches into May and September, the problem stops being occasional.

Days a year with a maximum of 35 °C or above in Vitoria. ERA5 reanalysis, 1995 to 2024.
Days ≥ 35 °CJanFebMarAprMayJunJulAugSepOctNovDec
Mean0.00.00.00.00.00.10.30.60.00.00.00.0

How it compares with the rest of Spain

Of the 17 regions with a page on this site, the Basque Country has the 12th-highest extreme-heat threshold (33.2 °C) and ranks 12th for days a year above it. For tropical nights it ranks 15th. For scale: the highest in the country is Seville at 40.0 °C, and the lowest Santa Cruz de Tenerife at 25.2 °C.

On how fast it is worsening it ranks 12th of 17. That is the figure worth watching rather than the threshold itself: the starting point depends on each place’s climate, but the increase can be compared across all of them.

Where these numbers come from

From ERA5-Land, the reanalysis produced by the European Centre for Medium-Range Weather Forecasts, downloaded from the Copernicus Climate Data Store under a CC-BY licence: hourly temperature between 1995-01-01 and 2024-12-06, 30 complete years, taken at the 42.80°, -2.70° cell, the closest to Vitoria. ERA5-Land runs on a grid of about 9 km and covers land only, which keeps the sea from cooling the figure in coastal cities.

One caveat that changes how all of this should be read: a reanalysis is not a weather station. It smooths the terrain and cannot see a city’s heat island, so its absolute extremes fall short of what AEMET measures at a specific observatory: here the highest value in the series is 39.0 °C. That is why the figure that governs this page is not a fixed threshold but the one specific to this place, and why the real value lies not in the record but in the comparison between decades: the series is long, homogeneous and without gaps, and there a reanalysis beats any station that has changed site or instrument along the way.