Another year that was too warm, too dry and this time very sunny - in short, these were the weather characteristics of 2020. 13.0 degrees Celsius was the average temperature for the year, which is 2.6 degrees Celsius more than the long-term average. This means that 2020 still beat the record of 2018 by 0.1 degrees - in 127 years of recorded weather. The coolest year in the last 127 years was 1940 with an average of 8.3 degrees Celsius. In the last 30 years, there have only been three years - most recently 1996 - with a negative deviation, but in contrast, there have been over 20 years with an annual average temperature of eleven degrees Celsius or more.

All months of the year were warmer than normal, also unprecedented in Bonn. The hottest day of the year was August 8, when Bonn residents sweated it out at 38.5 degrees Celsius in the afternoon. The lowest temperature of the entire year was recorded on November 30 with minus 4.4 degrees Celsius. In comparison, these were the highs and lows from the previous year: highest temperature: 41.9 degrees Celsius (July 25) and lowest temperature of minus 7.3 degrees Celsius (January 21). The most extreme temperatures of the last 127 years: on July 25, 2019 it reached 41.9 degrees Celsius and on January 27, 1942 it dipped to minus 23.8 degrees Celsius.

On 26 days (in 2019 it was 24) it climbed above the 30 degree Celsius mark, and on 75 days (70 days in 2019) it was more than 25 degrees Celsius in the shade. On the other hand, there were 17 (25) days where it dipped below 0 degrees Celsius.

There were 2,013 hours of sun (2019: 1,833), 180 hours more than the previous year. This takes second place in 52 years of observations. Only February, October and December had less sun than usual. The month with the least amount of sun was October. The sun shone longest in May with 303 hours.

2020 was also drier than usual: a total of 600 liters per square meter (675 liters per square yard) of precipitation fell on 169 days (192 the previous year), this is 21 percent below the long-term average. This ranks 108th in the city's 173-year rainfall chronicle. In 2020, 14 (18) storm days were recorded, with the strongest wind gust of 18 meters per second measured on August 18. Even though 2020's values are similar to those of the previous year, it reinforces the observations of recent years: Years that are hotter than usual are becoming more frequent, and they are often also more humid than usual (except for the last three years) and sunny.

Since 1895, annual temperatures have risen by an average of 2.0 degrees Celsius, and annual precipitation is now around 150 liters per square meter. In short, climate change has also arrived in Bonn.

Orig. text: Klaus Kosack

Translation: ck