Monthly review December 2021

The month of December was 1,4 degrees too warm compared to the reference period 1961-
1990 at the weather station Dresden-Klotzsche. With a monthly mean of 2.4 °C, it thus
belonged to the rather average December months since 1961, taking 21st place in the
ranking since 1961.

45 hours of sunshine were recorded, a value that was roughly in line with the long-term
average (compared to the official reference period 1961-1990).

The sum of all individual measurements of precipitation reached 42.9 mm in December at
our measuring station in Coswig (a minus of 7.4 mm). Thus, the monthly sum corresponded
to 85 % of the normal value for this month. We thus registered a too dry December in terms
of the total amount of precipitation that fell. The annual balance was nevertheless slightly
positive at 106 % thanks to the wet summer months of July and August. This summarily
compensated for the significantly too dry months of April, September and October.

Weather characteristics:
The characterization of the weather in the 3 decades of December can be roughly done in
the following way:
In the 1st decade, a repeatedly regenerating long-wave trough over Central Europe with cool
air determined the weather pattern in Saxony. On the 10th, a thin snow cover was formed
(Dresden-Klotzsche 3 cm).

The 2nd decade was mainly characterized by an area of high pressure over southern Central
Europe, with mild air masses prevailing.

In the 3rd decade, very dry cold air briefly broke in during the Christmas holidays. During
nightly clearing, temperatures could therefore drop far (Fig.1). On the last days of 2021, an
exceptionally mild episode followed due to the inflow of subtropical air originating from the
Canary Islands. On December 31, the highest temperatures were 16.1 °C in Garsebach (Fig.1)
and 15.1 °C in Dresden. It was not so mild in the whole December and November. The night
to 31.12. was so mild in Garsebach with a lowest temperature of 12.2 °C that it would have
easily passed as a cool summer night. This is also remarkable because very low minimum
temperatures of - 15.5 °C were measured shortly before at the night of the 2nd Christmas
Day.