Comparison of fog occurrence at Slovak international airports for the period 1998-2018

The aim of the paper is to analyze and compare the occurrence of fog at the international airports of the Slovak Republic in the years 1998-2018. The paper explains the influence of weather on the flight, the influence of meteorological conditions on visibility, defines the fog and describes the international airports - M. R. Štefánik Airport in Bratislava, Košice Airport, Poprad - Tatry Airport and Žilina Airport. Based on the analysis of METAR reports, we found that the average number of foggy days in the monitored period at Žilina Airport was 132.24 days per year. It is followed by Košice Airport (81.33 days), Poprad Airport (77.81 days) and Bratislava Airport (61.33 days). We attributed the high number of days with the occurrence of fog at Žilina Airport to its location, as there are up to nine water reservoirs and the main course of the Váh River in its vicinity. Bratislava Airport has ideal conditions in terms of visibility. According to METAR, 37 % of foggy days were recorded in autumn, 31% of foggy days in winter, 17 % of foggy days in summer and 15 % of foggy days in spring. At international airports, fog in the autumn meteorological period in the observed period from 1998 to 2018 occurred most often from 00:00 to 12:00, ie mainly in the morning and in the morning, with an incidence of 57 % to 71%.