Soil Temperatures Up to 54°C! Current Satellite Image Shows Extent of Heatwave in Europe

Using the Sea and Land Surface Temperature Radiometer (SLSTR), exceptionally high ground temperatures were measured, significantly exceeding the usual air temperatures.

Heat Dome Over Western Europe Intensifies Extreme Weather

The cause of this extreme heat is a so-called heat dome – a stationary high-pressure system that traps hot air masses over Western Europe. This phenomenon prevents cloud formation and leads to increased solar radiation, causing temperatures to rise further. Additionally, the heat dome draws hot air from North Africa to Europe, exacerbating the situation.

Record Levels Measured in Several Countries

Countries particularly affected include Spain, Portugal, and France, where temperatures of up to 46.6°C were recorded. New June temperature records were also noted in Austria. The persistent heat increases the risk of wildfires and significantly strains the health of the population.

Satellite Shows Scorching Hot Land Surfaces

The EU's Copernicus Sentinel-3 mission documented land surface temperatures on the morning of June 29, 2025, with a mosaic image from five satellite overpasses. These were significantly higher than air temperatures in many areas and show the actual thermal energy radiated from the ground. The surface of the Mediterranean Sea also showed unusually high temperatures, which increased humidity and heat stress further.

The Mediterranean Also Warming Unusually Strongly

The Copernicus data not only shows the extreme temperatures on land but also unusually warm water temperatures in the Mediterranean, which have additional impacts on the regional climate.

Experts warn that such extreme weather events could become more frequent and intense due to climate change. The population is urged to take precautions, drink enough water, and avoid physical exertion during the hottest times of the day.

Frequently Asked Questions About the Record Heat in Western Europe and Austria

What is a heat dome?
A heat dome is a stationary high-pressure area that traps hot air masses over a region. This results in few clouds, increased solar radiation, and further rising temperatures. Additionally, hot air from North Africa can be brought in, which further intensifies the heat.

Why are ground temperatures often significantly higher than air temperatures?
Ground temperatures measure the direct warming of the surface by solar radiation. They can be significantly higher than the measured air temperatures in strong sunlight and dry conditions.

Which regions of Europe are particularly affected?
Especially Spain, Portugal, and France report record values of over 46°C. New temperature records for June have also been set in Austria.

How unusual is the current heatwave in Austria?
June 2025 is the third warmest June since records began. In Carinthia, a new state heat record for June was reached with 38.3°C. New highs were also measured in other regions.

Were there regional differences in the heat in Austria?
Yes, during the first weeks of June, it was particularly hot in the west and south, while the north and east remained cooler at times. It was only in the last week of June that the heat affected the entire country.

How long did the current heatwave in Austria last?
In Klagenfurt and Ferlach, the longest June heatwave since records began was recorded, with more than ten consecutive hot days over 30°C.

How does the heat affect nature and agriculture in Austria?
The heat and drought delayed the flowering of grapevines, while early fruit varieties such as sweet cherries and currants ripened faster than usual.

Background: Sentinel-3 Satellites – Key to Monitoring Heatwaves

The Sentinel-3 mission is part of the European Copernicus Earth observation program, operated by the European Commission in collaboration with the European Space Agency (ESA). Sentinel-3 consists of several identical satellites (currently Sentinel-3A and 3B), specifically designed to monitor environmental and climate changes.

Making Heatwaves Visible: The SLSTR Instrument

The core of temperature measurement on Sentinel-3 is the Sea and Land Surface Temperature Radiometer (SLSTR). It measures the thermal radiation of the Earth's surface in multiple infrared channels with high accuracy. This allows the actual land and sea temperature to be recorded – independent of air temperatures, which are often lower than these values.

The SLSTR data make so-called "hotspots" visible, as documented during the current heatwave in Europe. This information not only helps in analyzing heatwaves but also in assessing health risks, wildfire hazards, and agricultural impacts.

Source: This article is partially based on information from the European Space Agency (ESA), as of July 1, 2025. www.esa.int

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