Looking at the results from a weather station where I live here in Pretoria, I find that winter here has been cooler than it was last year. The recorded temperatures in for May & June 2020 each are about 2 degrees lower than May and June last year (2019).
The oceans in the southern hemisphere are also getting cooler. See attached picture.
You might be inclined to think that this is just a fluke, or a one year incidence, but if you go over my report here,
Submission by Henry Pool (2018)
(just click on the above link)
you will note that there is a long term trend (measured over 40 years) of minimum temperatures dropping in South Africa.
This flies in the face of the theory of man made warming due to more carbon dioxide which implies that minimum temperatures should be rising, pushing up the average temperatures.
Something tells me that Europe and the USA are going to get a cold winter, too:
Is the drop in temperature only at night or during the day as well? It is not unknown that the Highveld nights can become extremely cold during winter. However, if the temperature also continues to drop significantly during daytime, I would believe your theory
The temperature drop of ca. 2 degrees C applies to minima, maxima and the mean temperature.
Where to find the original German article ?