22 January 2023

Climate Comparer

2022 was a year of record-breaking heat in Southwest Europe, with Portugal, Spain, France, and Italy experiencing some of the highest temperatures on record. But just how abnormal were these temperatures? To give a clear picture of the extent of the extreme temperatures, we compared them to 1990-2020 average in more than 20,000 locations around the world.

How extreme were 2022 temperatures in your city?

The results were striking: in 2022, cities in Southwest Europe experienced temperatures comparable to those of cities located, on average, 425 km further south. Madrid, for example, had temperatures similar to those found in Tissemsilt, a city in Algeria over 500 km to the south. Similarly, cities near the Alps in Italy such as Milan and Turin saw temperatures typical of Greece, and in France, even Brittany, known for its mild climate, had temperatures normally found in Spain.

Discover the data for yourself by clicking on a city to see the specific results, or click here to take a closer look by viewing the map in full screen.

Using Climate Comparer on tour own website

You can integrate the application anywhere on your site or blog. Just add this line to your html code where you want the interactive map to appear:

<iframe src="https://climatecomparer.climint.com/" scrolling="no" width="100%" height="700px"></iframe>

Methodology and sources

To build this interactive map, the monthly temperature in 2022 in selected locations in Europe was compared to the monthly temperature normal in over 20,000 cities worldwide over a period of 30 years (1991-2020).

  • Calculation of the most recent monthly normal for a list of cities in the world (i.e.: average monthly temperature over the period 1991-2020)
  • Calculation of monthly average temperatures in 2022 for major cities in Portugal, Spain, France and Italy
  • Evaluation of the mean square error and the maximum absolute error between the temperatures in 2022 of European cities and the normal in reference cities
  • Selection of the reference city with the lowest mean square error and, in case of equality (difference in MSE lower than 0.002), the lowest maximum absolute error
  • Calculation of the displacement on the north-south axis using the haversine formula.

All temperature data are from the ERA5 climate reanalysis.
ERA5 is a dataset produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). It provides a detailed and consistent record of the Earth’s climate, from 1959 to the present by combining observations from a variety of sources, such as weather stations and satellites, with computer models of the atmosphere and oceans. The spatial resolution of ERA5 is approximately 30 km (0.25 degree).

About Callendar

Callendar is a Paris-based startup that specializes in developing user-friendly, accessible, and actionable tools to help businesses and communities anticipate the impact of climate change. In 2022, it provided climate data and climate risk assessments to major utilities, infrastructure operators, and financial institutions, as well as more than 50,000 individuals.

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