Gregor J. Mendel is today best known for his discovery of the so-called Mendelian laws that he published in a long article in 1866. Most of his scientific papers however deal with meteorological topics. Of his overall 13 known articles written by him, 9 are devoted to meteorological or climatological observations. Since the first compilations of his work, this basically formed the core of his scientific publication work without any significant contributions extending the list. Here we report on an additional article that he published in 1857 reporting on a thunderstorm he observed in Brno on Friday, 7th August.
