WMO confirms verification of new continental European temperature record

30 January 2024

The World Meteorological Organization (WMO) has officially confirmed a new record temperature for continental Europe of 48.8°C (119.8°F) in Italy on 11 August 2021. The findings were published in the International Journal of Climatology.

Key messages
  • WMO experts verify 48.8 °C temperature in Sicilia, Italy, on 11 August 2021
  • Record occurred during extreme heatwave in Europe
  • WMO Weather and Climate Extremes Archive is snapshot of changing climate
  • Exhaustive evaluation underlines scientific rigor
  • Findings published in the International Journal of Climatology

An international panel of atmospheric scientists verified the temperature recorded by an automated weather station in Syracuse on the Italian island of Sicilia (Sicily). Because WMO Region VI (Europe) contains parts of Asia (e.g. Israel, Türkiye and Syria) and Greenland, the WMO extremes are categorized with records for both the region as a whole and for ‘continental’ Europe.

The previous record for continental Europe of 48.0 °C (10 July 1977) was held by the Greek cities of Athens and Elefsina, Greece. This was based on official government sources and included in the WMO Archive of Global Weather and Climate Extremes at the time of its formation in 2007. However, there was no independent WMO verification – unlike with the recent Italian temperature.

“The extremes presented before the WMO for adjudication are ‘snapshots’ of our current climate. It is possible, indeed likely, that greater extremes will occur across Europe in the future.  When such observations are made, new WMO evaluation committees will be formed to adjudicate such observations as extremes,” says Prof. Randall Cerveny, Rapporteur of Climate and Weather Extremes for WMO.

“Most investigations – like this one – are lengthy procedures because of the meticulous care that the WMO undertakes in certifying weather observations. Such painstaking evaluation provides the critical confidence that our global records of temperatures are properly being measured.  Beyond that, this investigation demonstrates the alarming tendency for continuing high temperature records to be set in specific regions of the world,” said Prof. Cerveny.

Many WMO evaluations are published in peer-reviewed journals such as the International Journal of Climatology. They are the included in the official website for the Archive of Weather and Climate Extremes, which includes records on the world’s highest and lowest temperatures, rainfall, heaviest hailstone, longest dry period, maximum gust of wind, longest lightning flash and weather-related mortalities.  

The WMO committee of experts is currently conducting a number of other investigations, including whether Tropical Cyclone Freddy broke the record last year as the longest-lasting tropical cyclone.

New adjudicated records provide an authoritative benchmark for comparing record extremes for the annual WMO State of the Climate reports at global and regional scales.   

A map showing the location of sicily.
Sicily map with temperature

In-depth investigation

The WMO committee conducted an in-depth analysis of available data and metadata, including an independent analysis and calibration of the Siracusa sensor and its associated datalogger and solar shield.  The Sicily temperature sensor was sent to the Instituto Nazionale di Ricerca Metrologica (INRiIM), Italy for testing. The activities involved calibration and evaluation of the entire system (sensor, solar shield and datalogger), in the same configuration as when it was recording at the time of the extreme temperature occurrence. The testing was consistent with all WMO Standards and recommended practices.

Additionally, the committee determined that in August of 2021, a very strong upper-level ridge was in place over the region at the time of the extreme temperature.  Data from reanalyses and from other nearby sites was in accord with the extreme temperature observation.  The committee unanimously deemed the 48.8⁰C observation valid.

Details on the working of the WMO Extremes Archive and past evaluations are presented in a forthcoming book by Randy Cerveny entitled “Judging Extreme Weather : Climate Science in Action” to be published by Routledge Publishing. 

The World Meteorological Organization (WMO) is a specialized agency of the United Nations responsible for promoting international cooperation in atmospheric science and meteorology.

WMO monitors weather, climate, and water resources and provides support to its Members in forecasting and disaster mitigation. The organization is committed to advancing scientific knowledge and improving public safety and well-being through its work.

For further information, please contact:

  • Clare Nullis WMO media officer cnullis@wmo.int +41 79 709 13 97
  • WMO Strategic Communication Office Media Contact media@wmo.int