As your link points out, in Dutch this is also known as "komkommertijd" ("cucumber time"), and in German as "Sauregurkenzeit", ("pickled cucumber time").

The funny thing is that apparently "cucumber time" also existed as an expression in English for a while in the 18th century. One suggested etymological origin for the Dutch "komkommertijd" was as a loan work from the English around the same period, except ttat it survived after the English stopped using it. According to some sources cited on the Dutch wiki page the expression was mainly used by German tailors in London.

[0] https://nl.wikipedia.org/wiki/Komkommertijd

The modern German equivalent would probably be "Sommerloch" [1], describing the time when most politics is on hold because of summer vacations and news outlets try to fill the void with whatever story they find. The usual writers and editors being on vacation too during this time doesn't help.

- [1] https://de.wikipedia.org/wiki/Sommerloch (links to "silly season")

In Hebrew too - עונת המלפפונים - cucumber season