How hot was it in 2015?

Over 150 years of Swiss weather data illustrates our changing climate, after one of the warmest years on record. While the summer was scorching hot, December turned out be unusually mild.

Since 1864 – when weather data collection started in Switzerland – it has never been as hot as in 2015. Summer saw record temperatures on the plains of western, French-speaking Switzerland and in the Italian-speaking south.

In winter, it was in the mountains where the impact of the warmer temperatures was felt the most, particularly on winter tourism. The animated graphic below shows how temperatures at higher altitudes have evolved over 150 years. For the first time, the average temperature for the month of December exceeded 0°C.

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In 2015, the average temperature also reached record levels for the whole of Switzerland.

A global situation

Experts have observed the same warming trend on an international level. Even though all the data for 2015 has not yet been published, it appears that last year was the warmest since 1880.

The World Meteorological Organization (WMO) recently announced that the global average temperature is expected to reach a record level in 2015 and exceed the threshold of a 1°C rise compared to the pre-industrial era. According to the WMO extreme temperatures are due to a combination of a particularly strong El Niño along with man-made greenhouse gas emissions. El Niño is a cyclical climate phenomenon resulting in a warming of the waters of the equatorial Pacific Ocean and can cause severe droughts or heavy rainfall in different regions.

Further reading:

Evolution in global temperaturesExternal link up until 2014 and model use for the animated graphic.