of the Winter War at a weekly basis
Based mostly on the timeline found
at "Talvisodan Pikkujättiläinen", p.163 - 179
Thursday 30 November 1939
- Sunday 3 December 1939
The war began in mild temperatures. Helsinki had +2 Celsius and
Vyborg 0 Celsius. In Ladoga Karelia at Loimola (east of Sortavala),
the temperature was -2.8 Celsius and some 10 cm of snow. By Sunday,
the temperatures dropped a little, still being near 0 in most parts
of the country. Up north in Sodankylä Lapland however, the
temperature fell rapidly on Friday to -23.4 Celsius (at 21:00 PM)
but the next evening (2 Dec) warming to a milder -10.4 Celsius and
to -3.7 Celsius on Sunday evening.
Monday 4 December 1939 - Sunday 10 December
The second week of the war started off in somewhat mild temperatures
until it started to get cold on 8 December. After two days of
cold (coldest temperature in Sodankylä was -19.9 Celsius),
it got a little warmer on Sunday, being -8 C in Helsinki, -11.2
C in Sortavala and -8.1 C in Sodankylä.
Monday 11 December 1939 - Sunday 17
The third week of the war began with two days of cold (ranging
from -6.4 to -16.4 Celsius at Sodankylä in Lapland to around
-10 Celsius in Sortavala). On Wednesday, the cold receded and the
temperatures for the next two days throughout the country were roughly
from 0 to -7 Celsius. On Friday it got a little colder again, until
on Sunday the wind brought warm air from the Southwest which brought
temperatures throughout Finland close to zero Celsius, even above
it in many places.
Monday 18 December 1939 - Sunday 24
Up to this fourth week, the temperatures had been relatively mild,
considering usual winter time temperatures. Monday and Tuesday were
very mild days, during which the warmest days of December were recorded
in most parts of Finland (+3 Celsius in Viipuri and Helsinki, +2.2
Celsius in Sortavala and even +3.3 Celsius in Sodankylä Lapland).
But on 20 December the temperature started to drop sharply (on average
to about -4 C in the Aaland Islands, -7 C in Helsinki, -10 C in
Viipuri, -14 C in Sortavala and about -14.5 C in Sodankylä).
On Thursday it snowed almost throughout Finland, which continued
on Friday warming the weather. But on Saturday it got cold again.
On Christmas Eve Helsinki had -15 C, Viipuri -18 C, Sortavala -22
C and -27 C in Sodankylä.
Monday 25 December 1939 - Sunday 31
The last week of the year 1939 (fifth of the war) started off
in cold temperatures. In many parts of the country Monday and
Tuesday were the days when the coldest temperatures so far were
reached. On 25 December, -23 C was measured in Kuopio and Jyväskylä
while on 26 December -19 C was measured in Helsinki, -25 C in
Viipuri, -26 C in Sortavala, -29 C in Kajaani and -23 C in Oulu
and -29 C in Sodankylä.
On the next days, the temperatures varied widely, when Southern
Finland got warmer while Lapland got colder, the coldest temperature
of December that was measured in Sodankylä was on the last
day of the year being -34.3 degrees below zero.
Monday 1 January 1940 - Sunday 7 January
The year 1940 (and the sixth week) began in the clutches of cold
but mostly sunny weather, the temperatures being around -20 degrees
below zero elsewhere except in the Aaland Islands where the temperature
was considerably higher. The next day, on Tuesday, the cold receded
when it began to snow everywhere. In Ladoga Karelia, the wind was
blowing from the Lake Ladoga (even 20 m/s wind speeds were measured)
clogging the roads in the area. The next day dawned with a sunny
weather only to see the strong wind and the snowfall to start again.
The Finnish 12th Division weather station measured the wind speed:
11 m/s while the temperature was -11.8 Celsius. After the snowfall
ended, the temperature got colder again. On Saturday, 6 January,
the temperatures were around or below -20 Celsius (-23 C in Viipuri,
-26 in Oulu and -23 C in Sodankylä).
Monday 8 January 1940 - Sunday 14 January
Seventh week. While Monday was still quite cold, the weather
got warmer again on Tuesday. The next five days were relatively
mild, rising by Saturday even above zero in most parts of Finland
(the warmest period of January, 12 January the warmest recorded
temperatures were: +3 in Viipuri, 0 in Kuopio, +1 C in Kajaani
and +1 C in Sodankylä. On 13 January there was +4 C in Helsinki
and +2 C in Jyväskylä). It also snowed in most parts
of Finland (according to the Finnish 12th Division records, "+0.4
Celsius and sleet"). On Sunday the wind changed and cold
air began to come from the north.
Monday 15 January 1940 - Sunday 21 January
The eighth week of the war was the coldest week of the winter
1939-1940. It was this week that made the weather of the Winter
For 4 consecutive days, from Monday to Thursday, the temperature
was extremely cold due to a wind blowing from the northeast and
17 January was the coldest day of the war and at least the following
places recorded their lowest daily temperatures: -33 C in Helsinki,
-38 C in Viipuri, -38 C in Jyväskylä and -38 C in Kajaani.
On other places, like in Koivisto (in the Karelian Isthmus, on
the shore of the Gulf of Finland), the temperature in the morning
was a numbing -45 degrees below zero, and in Summa before dawn,
a -49 Celsius temperature was reported, while in Taipale the temperature
around noon was -39 Celsius. In Ladoga Karelia, -42 Celsius was
measured in Loimola.
(Note that the temperatures measured in the morning were much
colder than the temperatures measured during the day, i.e. the
noon temperature in Summa was above -49 below zero, while the
temperature in Taipale before sunrise was probably below -39 Celsius.)
On this day the whole Lake Ladoga froze.
On Friday, the temperatures rose about 10 degrees, being -20
C in Viipuri and -23 C in Sodankylä
Monday 22 January 1940 - Sunday 28 January
The ninth week of the war started in temperatures ranging from
about -10 Celsius in Southern Finland to about -30 Celsius in
Lapland (-27 C in Sodankylä). Up north in Lapland the temperatures
remained cold while the worst cold had receded from the mid and
southern parts of Finland. 23 January was the coldest day of January
in Sodankylä, -38.1 degrees below zero.
Monday 29 January 1940 - Sunday 4 February
The tenth week was similar to the previous week, around -10 Celsius
in the southern parts of Finland. Later in the week it got a little
Monday 5 February 1940 - Sunday 11 February
The 11th week was quite cold (temperatures fluctuating from about
-10 C to -20 C in most parts of Finland). During the week all
of Finland received snow. Friday was the coldest day of the week
for mid- and southern Finland, Helsinki having -24 C, Kuopio -
20 C, while the in Lapland it got warmer, Sodankylä having
only 9.5 Celsius (the mild period in Lapland continued to 12 February,
on Saturday evening Sodankylä had a mild temperature of -3.5
degrees below zero).
On 11 February, the day when the Great Offensive of the Red Army
in the Karelian Isthmus began, the temperatures throughout most
of the Karelian Isthmus about -20 Celsius.
Monday 12 February 1940 - Sunday 18
While heavy fighting was going on in the Karelian Isthmus, the
temperatures during the 12th week of the war, varied from about
-10 C to -24 C. On 15 February it got colder in the eastern part
of Finland, Kuopio having -29 C and Jyväskylä -33 C.
In Sodankylä, the coldest morning (07:00 AM) temperature
of February was measured on 17 February: -39.2 degrees below zero
(the average 17 February temperature in Sodankylä was -31
Monday 19 February 1940 - Sunday 25
While the 13th week of the war saw Lapland having a somewhat
mild temperature, only -12 C in Sodankylä, further south
the temperatures were on average around -20 degrees below zero.
On Friday, the wind shifted, starting to blow warmer air from
the south and west, with the result that Helsinki had a +1 Celsius
temperature on Saturday. A lot of snow fell during this week,
most of it between 20 - 24 February. On Sunday, after the snowfall
ended, the weather got colder again.
Monday 26 February 1940 - Sunday 3 March
14th week. While the temperature on Monday was still subzero,
on Tuesday it started to get warmer again with plenty of snowfall
in eastern Finland. On 28 February, the warmest day of February
was recorded in the following places: Aaland Islands +3 C, Jyväskylä
+2 C and Kajaani +2 C above zero. In Lapland however, the weather
remained cold for a few more days, around -15 degrees below zero.
On Sunday it started yet again to get a little colder. -6 C in
Helsinki, -5 in Oulu and -7 in Sodankylä. At the same time
Lapland received some snowfall.
Monday 4 March 1940 - Sunday 10 March
On the 15th and last full week of the war, the wind changed yet
again and cold air began to pour from the north. This kept the
temperatures well below zero degrees, Friday being the coldest
day of the week (Helsinki -8 C, Kuopio -9 C, Oulu -19 C and Sodankylä
-12 degrees below zero).
Monday 11 March 1940 - Tuesday 13 March
Both Monday and Tuesday were days when there was a lot of snowfall
in South Finland, especially in Southeastern Finland, and on Tuesday
mostly around Viipuri. On 13 March, Helsinki had -10 C, Kuopio -14
C, Oulu -16 C and Sodankylä -24 degrees below zero.