Analysis of an Occurrence of High Frosts During the Growing Season in Central-East Poland in 2001-2018

Frosts are the most common natural phenomena during the transitional seasons. A frost occurs when the average daily air temperature is positive and the minimum temperature drops below 0°C. The problem of frost occurrence (especially spring frosts) is very important from the point of view of the threats related to crop plant cultivation, because it causes losses in crops when taking place during the plant growth. The aim of the study was to analyze the occurrence of air frosts in the years 2001-2018 in the region of central-eastern Poland on the basis of meteorological data. In the region of central-eastern Poland, the greatest number of days with mild, moderate and strong frosts in 2001-2018 was observed in Białowieża; conversely, it was the lowest in Warsaw. The distribution of the number of days with frosts in spring was similar. The distribution of autumn frosts, however, was different. The greatest number of days with autumn frosts was observed in Terespol and Białowieża, the least in Legionowo and Warsaw. The last mild spring frosts occurred in the period from the 3rd to 7th of April, and the earliest autumn frosts occurred between the 9th of September and the 27th of October. The dates of moderate frosts were similar. The last strong frosts occurred on the 2nd of May and the earliest on the 30th of September. The conducted analysis proved that in such a small area, there is a difference in the occurrence of high frosts observed both in spring and autumn