Maximum temperature, NWS heat index, humidex and 7-day forecast for Santander and the rest of Cantabria. AEMET regional record: 42.0 °C (near Vitoria, August 2003).
| Day | T max | Feels-like max | Over threshold |
|---|---|---|---|
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Real-time Open-Meteo data.
Cantabria 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 (near Vitoria, 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.
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 Cantabria.
The 7-day forecast box shows expected highs and maximum feels-like temperatures for Santander. 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 Cantabria. Check official AEMET warnings at aemet.es.
As in Asturias, real heat in Cantabria is brought by a southerly wind. The cordillera acts as a barrier and the air that crosses it descends overheated towards Santander and the coast, in episodes that last briefly and are remembered for a long time. With a northerly, the Bay of Biscay holds the maxima down for weeks at a stretch.
35 °C does not mean the same thing in Córdoba as in Santander, so a fixed number is the wrong place to start. Taking Santander 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 29.3 °C, well down the national range, as you would expect where the sea is never far away. It is exceeded on about 6 days a year.
In absolute terms that is 0 days a year at 35 °C or above and 0.0 at 40 °C or above, with a mean August maximum of 23.8 °C. The nights count as much as the days: there are 2 nights a year when the temperature does not drop below 20 °C, though 25 is virtually never held.
That is the question that matters most, and the series answers it on its own. In Santander, days above that 29.3 °C threshold went from 4.3 a year on average in 1995-2004 to 8.0 in 2015-2024. The gap is large and points one way only: 4 more days a year above the threshold, 86 % more than thirty years ago. Nights that do not drop below 20 °C have made the same journey: from 1 to 2 a year.
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 Santander stands at 29.3 °C, and across 30 years of record 12 episodes have occurred. The longest ran 8 days in a row. The hottest day in the whole series was 11 August 2024, at 40.1 °C.
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 ≥ 35 °C | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.2 | 0.2 | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 |
Of the 17 regions with a page on this site, Cantabria has the 15th-highest extreme-heat threshold (29.3 °C) and ranks 1st for days a year above it. For tropical nights it ranks 14th. 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 11th 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.
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 43.40°, -3.70° cell, the closest to Santander. 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 40.1 °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.
