The impact of winter weather at the two major airports in Germany

The impact of winter weather on the punctuality at the two largest German airports, Frankfurt and Munich, is analyzed. A climatologic analysis of winter weather at both airports serves as background against which the actual impact of weather phenomena such as snow, temperature, ground frost, freezing precipitation on daily punctualities is assessed. A linear regression method is used to determine the total impact and to derive a ranking among the various winter phenomena. The various factors are discussed and compared between Frankfurt and Munich. Snowfall and snow cover have a strong impact, especially when they occur simultaneously. Punctualities are then reduced by 10 - 15 percentage points, on the average. In contrast, frost and ground frost were found to be insignificant. Delays due to winter weather conditions arise when winter services become necessary. The two major ones are (1) surface de-icing and runway clearance, and (2) aircraft de-icing. The magnitude of both effects depends significantly on the organisational structure of the winter services, e.g. on the number of de-icing pads. Thus the winter impact depends on both weather conditions and winter service organisation. Winter services at the two airports are organized in a completely different way, with significant impacts e.g. on the requested meteorological forecast horizon. While in Frankfurt an airport owned company handles all the surface winter operations, in Munich a contract model with farmers of the neighbouring villages is preferred. Here only a forecast time of 1 hour is required while in Frankfurt 12 hour forecasts are needed. The overall winter impact on punctuality at both airports is assessed and discussed.