A distinction is also made between the observation times noon and midnight (ascents of the balloon soundings).

The statistics show that inversions immediately above the ground (ground inversions), indicating a stable thermal stratification of the air in the ground layer with cold air at the bottom (0-200 m), are to be expected in 70 % of all nights per year.

This frequency reaches even 83 % up to an altitude of 700 m. These inversions occur in 40 % of all cases even during the day (noon).

Ground inversions at daytime occur preferentially in autumn and winter months as insolation and therefore the warming of the air in the ground layer is minor then.

Night inversions occur most frequently between May and October, but they are not very powerful and usually dissolve during the day.