The winter of 2021/2022 started early in Helsinki and Finland in general. On the 25th of November, the temperature dropped below 0 and it stayed (far) below zero for the rest of the month: a cold end of the month in Helsinki!
November in that sense followed up on the preceding autumn months. It was my 2nd year in Finland and my experience was that the fall of ’21 was way colder (and wetter) than that of the previous year. I checked the statistics and it turned out that my gut was correct: late summer and fall of 2021 were indeed much colder than in 2020. However, the temperature was not too much below the climatological average.
Already during the first half of the month, we had quite some frosty nights, especially north of the city center (where I live). On the 9th of November, the temperature sunk to almost -9°C at the weather station of the Helsinki-Vantaa airport in the early morning. For a Dutch person, these kind of temperatures are quite special, especially for early November. In The Netherlands we have winters where we don’t even measure those kind of temperatures at all.
First (tiny) snowcover
Halfway through the month, some more frosty nights followed. One morning, I unexpectedly woke up to a tiny snow cover. This snow cover was very local, a few kilometers further, there was no snow at all. Presumably, it was industrial snowfall. This same day, we had to let up a weather balloon for university.
Completely unexpected, the first (very thin) snow cover this morning! Actual temperature -3° pic.twitter.com/IRX06r7UDF
— Daan (@Daaanvdb) November 15, 2021
Serious winter weather in November
On the 22nd of November, the first ice day (maximum temperature below 0) was measured at the airport. The maximum temperature in the city center was about a degree above 0. A few warmer days followed again (although it kept freezing during the nights) before the temperature plummeted again on the 25th of November. The last four days of the month, the maximum (!) temperature was around -5. During the nights, the temperature went down to -10.
Nuuksio just after sunrise, the lake almost completely froze over. pic.twitter.com/U3aZLDHVuH
— Daan (@Daaanvdb) November 21, 2021
1 night's ice growth😱 currently -7° pic.twitter.com/qqAddqSf5M— Daan (@Daaanvdb) November 27, 2021
Synoptic weather situation
During a big part of November, we saw the tendency for ridges building up over the Northern Atlantic and in the area of Scandinavia. Towards the end of the month, this ridge finally managed to build up and connect to a high forming over Greenland. A deep trough spread out over Europe, causing cold air to conquer Scandinavia. In Finland, the winds were between north and east for most of the time, advecting cold air.
Statistics for the ‘cold’ November in Helsinki
However the end of the month was quite cold, November itself was not very cold at all. Moreover, the average temperature of November was above the climatological norm of 1991-2020 with a temperature of 2.7°C (against a climatological average of 2.4°C) in Kaisaniemi and 1.5°C (against a climatological average of 1.2°C) at the Helsinki-Vantaa airport. It was however much colder than November 2021, which was the warmest November on record with an average temperature of 5.6°C in Kaisaniemi and 1.5°C at the Helsinki-Vantaa airport.
In the histograms shown above and below can be seen that both the maximum and minimum temperatures were much lower in November 2022 compared to November 2021. Remarkable is the peak of the low temperatures. The distribution doesn’t really smooth out towards the negative values, instead, there is a peak at very low values.
In Kaisaniemi, on 25 days, the maximum temperature was lower in November 2021 compared to 202. On 21 days, the minimum temperature was lower in November 2021. These numbers are the same for the weather station Helsinki-Vantaa airport.
In Helsinki-Vantaa (Kaisaniemi), the maximum temperature was below -5°C on 4 (2) days and the minimum temperature was below -5°C on 8 (4) days, 7 (4) days more than in the previous year. The maximum temperature went below 0°C on 5 (4) days, the minimum temperature on 17 (14) days, 5 (9) days more than in 2021.