Vol. 70, No. 1 * Pages 1–68 * January 2025

On the global scale, the summer of 2024 was the hottest summer since measurements began, and this contained extremes in Hungary's weather, too. The fifth warmest June on record was followed by the warmest July ever. August 2024 was the second warmest, just 0.01 degrees behind August 1992. The heat in July and August was accompanied by long dry periods. The summer in Central Europe, which lasted into September, ended with an extremely rainy period, causing severe floods. The summer, covered by long dry and short wet, but warmer than average weather periods in all cases, has a well-defined global background, which can be traced back to anomalies in the large-scale circulation. This paper presents the circulation background behind the extremes on the one hand, and the weather characteristics of summer heat waves in light of it on the other.

On 9 June 2024, a partially merged pair of supercells reached the western border of Hungary from Austria, from which the leading cell produced a relatively long-lived tornado. The vortex affected both Austrian and Hungarian areas, causing significant damage, predominantly in uninhabited regions. This study analyzes the synoptic processes that facilitated the development of the supercells and the tornado, including the role of the supercell merging in the tornado genesis. Additionally, we present the results of detailed damage surveys conducted in Hungary and incorporate reports from Austrian storm chasers and eyewitnesses to provide a comprehensive overview of the tornado's impacts.

Over the past decade, the installed capacity of solar power plants has increased significantly worldwide, and this growth is expected to continue in the future. However, the amount of electricity generated from solar energy largely depends on meteorological conditions. Consequently, quantifying future changes in photovoltaic power output due to climate change has become a popular topic in climatological research. This paper provides an overview of projected changes in photovoltaic power output by the end of the 21st century, based on simulation results from general circulation models.

Net radiation and evapotranspiration data show a significant increase in the Danube river basin, when comparing the 1961-1990 and 1991-2020 normal periods. The state of the energy and water balance, its changes and the effects of climate change can be graphically represented using a new method of plotting an operating point or working point of the energy flow. Based on its properties, the diagram can be called a climatic energy balance diagram, or climate diagram for short. A normalised climate diagram can also be used to compare conditions under different climates. The available previously measured data can also be plotted. The evaporation fraction can be used to express the Bowen ratio, or conversely, the evaporation fraction can be expressed in terms of the Bowen ratio.

Recently a significant amount of extra SYNOP (surface synoptic observation) data became available from the surrounding countries of Hungary, and it makes possible to include them into the AROME (Applications of Research to Operations at Mesoscale) data assimilation system. The study reviews the results of the expansion, during which it was concluded that the new observations – obtained via bilateral agreements – can be used in the data assimilation just as the data available through the GTS (Global Telecommunication System), since they have a similar quality. Furthermore, the development of the system was accompanied by a minimal improvement in the forecast quality.

In 2023, the World Meteorological Organization (WMO) celebrated the 150th anniversary of the founding of its predecessor, the International Meteorological Organization (IMO) established in 1873; while 2025 commemorates the 75th anniversary of WMO becoming the specialised agency of the United Nations. WMO was renamed at that time, and fulfils its mission of the worldwide coordination of meteorological activities since then. In this paper we provide a broad overview of the history and activities of these two organisations, complementing former relevant Hungarian publications. We give an insight of how the meteorological Global Observation Network, and later the World Organisation, was born from the ambitions of our predecessors. We also explain how the WMO operates today in the 21st century and how it relates to key global challenges.