Long-term variation in thermal strain on the human body in the region of Siedlce

Abstract

Aim of the studyAs a result of the increase in average air temperature associated with the present-day climate change, heatwaves are forecast to occur with increasing frequency. What is more, they will be longer, more intense, and potentially very dangerous for human health and life. The present work reports the day-to-day variation in air temperature and the variation of thermally characteristic days in Siedlce from 2001 to 2023.Material and methodsDay-to-day values of average and maximum air temperatures were obtained from the Siedlce Meteorological Station. The day-to-day variation in air temperature was determined across six ranges, and their frequencies in each month were calculated. Additionally, based on the maximum temperature, the number of thermally characteristic days (from cold to hot) was identified, and sequences of hot and very hot days were determined. The direction of trends in the number of hot and very hot days was also established.Results and conclusionsIn the Siedlce region, days marked by significant day-to-day temperature changes occurred on average 4.8 days per year, them being the most frequent in January (5.5 days/year) and least frequent in October (3.7 days/year). Comparing the number of hot and very hot days between the periods 2001-2012 and 2013-2023, an increase of about 6 hot days and 3 very hot days was observed. The trend coefficients for these changes were also positive, amounting to 0.43 and 0.24 days, respectively. The most frequent were sequences of hot days which were 4 to 6 days long.