Librarians at the National Research Institute for Physics collect summer opening hours notices of Hungarian libraries. Thanks to their work anyone with basic language skills can get an overview of the dates.

Here is the extract plus info about the Hungarian National Széchényi Library.

The Széchényi Library gets closed 1-31 August.

The main building of the Budapest Szabó Ervin Public Library is going to be closed 4-31 July.

The Library of the Hungarian Academy of Sciences closes on 27 June and reopens on 8 August, according to the above compilation.

The ELTE (Budapest) University Library closes on 11 July and opens again only on after 2 September.

The Library of the Parliament offers shortened opening hours in July, and closes in August.

The National Pedagogical Library and Museum is closed between 18 July and 21 August.

So, for the casual visitor the bottom line is: go to the National Széchényi Library if you plan a general research during July, and go to the Budapest Public Library or to the Academy Library if you do research during August.