The hydrographic network is not rich, despite the fact that two large rivers, the Danube and the Tisza, cross the country, as has been said. The Danube (or Duna) over a total length of 2850 km is in fact Hungarian only for just over 400 km, and of these a good third runs along the border. The river, which entered the Kisalföld through the narrow Hungarian Gate, soon blocked the path from the pre-carpathian reliefs, so that it turns to the S; it reduces the slope by wandering slowly in a widely flooded area where it stops in numerous meanders and is divided into arms that circumscribe elongated islands, among which the most important is that of Csepel. Although it is subject to lean and its flow reaches maximum peaks only in the summer months and although it is poor in tributaries, the Danube is navigable for almost the whole year and constitutes the true axis of the country; it is also particularly important for Budapest, to which it supplies water. The Tisza (or Tisza) crosses Hungary for approx. 600 km with course roughly parallel to that of the Danube; its path is very slow, sinuous, and the variations in its flow are remarkable, with maximums coinciding with the spring melting of the snows and with minimums at the end of summer; in crossing a heavily depressed area until the last century the waters of the Tisza frequently overflowed, while today dams and canals have greatly reduced the danger of serious flooding. Hungary has the largest lake in the Balaton, a fundamental element of Hungarian hydrography. Shallow (on average only 3 m, with a maximum of 11 m), this “sea of the Hungarians”, on whose shores well-known tourist and spa resorts overlook, is subject to violent storms despite the outflow having been regulated with locks of its outlet, the Sió, a right tributary of the Danube. Other lakes are the aforementioned Fertö and the small Velence. The soil is rich in water tables, thanks to which it has been possible to greatly increase irrigation and water supply to cities and industries.
According to ehealthfacts, the climate, given the geographical location of the country is sharply continental with strong temperature changes both daily or annual; in some places, maximum values of 41 ºC and more and minimums of –34 ºC can be found. In Budapest there are usually annual averages of 11-12 ºC with averages in January around –1 ºC and in July around 22 ºC. Throughout the country, however, the variability of the climate is remarkable, as this is conditioned by the alternation of the summer predominance of the air masses of Mediterranean origin and the winter one of anticyclones. continental coming from NE. In the transitional seasons the Atlantic influences, responsible for the precipitations, which are also quite variable, are relevant; on the whole, however, they are scarce, generally more abundant in early summer (June-July) with average values in autumn; the maximum quantities occur on the western reliefs (approx. 1000 mm per year) and the minimum in the eastern, steppe region (less than 600 mm per year); in Budapest they are of the order of 800 mm per year.
The natural landscape of Hungary is affected by the massive interventions carried out by man over time, aimed above all at creating ever new spaces to be used for crops (which in 2000 occupied 52% of the national territory). The environment, in its original aspect, is therefore limited to increasingly restricted areas, which often coincide with the mountainous regions and less suitable for exploitation by the population. The climate and the composition of the soil have a noticeable impact on the vegetation: luxuriant woods, composed especially of oaks and other broad-leaved trees, remain on the hills, while the higher elevations are covered with coniferous forests; large areas of the Alföld are still occupied by the puszta, the characteristic steppe Hungarian with Lössic soils, once the domain of nomadic breeding, however also progressively absorbed by crops; here, however, many species of migratory birds still find refuge, including the heron, the crane and the stork. Deer and wild boar abound in the forests at high altitudes, while hare, partridge and pheasant inhabit the plains in large numbers. Freshwater fish include bream, pike and carp. The serious environmental problems of Hungary have been caused by the rapid and often uncontrolled industrial development of the country and are constituted, in particular, by air, water and soil pollution. Air pollution, mainly caused by exhaust emissions from cars and power plants, it is particularly intense in the metropolitan area of Budapest, where the problem of thermal inversion is added to the massive nitrogen oxide emissions in winter, with a consequent surge in smog levels. In addition, the country’s forest and fruit and vegetable heritage, waterways and buildings are seriously threatened by the harmful effects of acid rain. The condition of the Danube is also precarious, which collects civil and industrial waste from the capital’s basin, as well as large quantities of pesticides and fertilizers used in the agricultural areas of the Hungarian nation. The International Commission of the Danube is located in Budapest, which has the task of monitoring the state of health of the great river. Still on the water pollution front, in January 2000, an accident in a Romanian gold mine caused an enormous quantity of cyanide to spill into the waters of the Tisza, a tributary of the Danube, causing an enormous environmental disaster. The accident seriously compromised the biological life of the river, causing the death of numerous species of fish, birds and mammals in Romania, Hungary, Serbia and the Black Sea. Lake Balaton is also affected by the presence of excessive levels of pollutants. Starting from the last years of the twentieth century, a greater sensitivity towards the environmental heritage has developed; forest areas make up 19.9% (2000) of the territory of Hungary, but reforestation initiatives have allowed the country to regain some portions of wooded land. On the 5th, 6% of the national territory is subject to environmental protection. Among the numerous national parks and nature reserves, the leading role belongs to the Hortobágyi National Park, a vast area of grasslands and wetlands, recognized by UNESCO as a World Heritage Site (1999) together with the Aggtelek karst formations; the National Park of the Bükk mountains should also be mentioned, which extends over a mountainous area of over 40,000 hectares. Hungary has signed various international environmental treaties, including those relating to air pollution, the elimination of discharges into the sea, wetlands, biodiversity, endangered species and toxic and harmful waste. The Eastern European Environmental Protection Agency is located in the Hungarian capital.