Human-biometeorological conditions during heat waves in Poland

The primary objective of the paper was the description of human-biometeorological conditions during heat waves in Poland in the years 1966-2018. The description is based on the human-biometeorological index Physiologically Equivalent Temperature (PET). The research was based on data obtained from the Institute of Meteorology and Water Management-National Research Institute for 30 stations in Poland. A heat wave was defined as a sequence of at least 3 days with a maximum daily air temperature of >30 degrees C. The research revealed increasingly frequent occurrence of heat waves in the territory of Poland. The highest number of heat waves was recorded in the western and southern regions of the country, and the lowest in coastal stations. In a large majority of stations, the longest heat waves occurred at the turn of July and August 1994 and in the first half of August 2015. In the case of two longest heat waves, human-biometeorological conditions were similar, although they were more strenuous during the heat wave in 1994. During that wave, considerably higher maximum PET values were recorded, but days with strong heat stress and extreme heat stress were also more frequent.