The average monthly temperatures were normal or slightly lower at the valley floor, while at altitude they turned out to be about 1 ° C above average, a consequence of the many days of high pressure, with very mild air at the upper levels.
BELLUNO. A December with little rain / snow, slightly colder than usual at the bottom of the valley and warmer at altitude. The last month of 2021 – Arpav records – proved to be very “dynamic” until day 9, for a phase characterized by the transit of some perturbations, a phase that had begun at the end of November. Subsequently, a powerful high pressure field affected the Alps for the entire second decade, and then reappeared in the last two days, after its failure between the 24th and the 26th.
“The average monthly temperatures – reads a note – were normal or slightly lower at the valley floor, while at altitude they turned out to be about 1 ° C higher than average, a consequence of the many days of high pressure, with very mild air at levels superior. The result was a prolonged, marked thermal inversion from day 12 to day 20 and even more accentuated on days 30 and 31. First decade rather cold, second very hot at altitude and third decade initially cold and then irregularly milder, especially at altitude in the last 2 days .. The freezing point varied between a minimum of 820 m on day 7 and a maximum of 3480 m on day 31. The average temperature of 2021 in the capital was 0.2 ° C lower than normal. Total monthly rainfall has been quite low, almost everywhere less than half of what is considered normal for this month. Practically all the rainfall of the month was concentrated in the first 9 days, with accumulations generally between 25 and 70 mm. In this phase, the snow also fell frequently in the pre-alpine valley floors, even copiously in the afternoon of day 8. The pluviometric balance of 2021 did not show significant anomalies, with negative differences everywhere below 20% ».