Editing Helsinki (section)

===Climate===
Helsinki has a cold [[hemiboreal]] [[humid continental climate]] ([[Köppen climate classification|Köppen]]: ''Dfb'', [[Trewartha climate classification|Trewartha]] ''Dcbo'').<ref>{{cite web |title=Climate Helsinki: Temperature, Climograph, Climate table for Helsinki - Climate-Data.org |url=https://en.climate-data.org/location/5971/ |access-date=17 January 2018 |website=en.climate-data.org}}</ref> Due to the moderating influence of the [[Baltic Sea]] and the [[North Atlantic Current]] (see also [[Extratropical cyclone]]), winter temperatures are higher than the northern location would suggest, with an average of {{convert|-4|C|F}} in January and February.<ref name="fmiclimate">{{cite web |title=Climatological statistics for the normal period 1971–2000 |url=http://en.ilmatieteenlaitos.fi/normal-period-1981-2010 |access-date=13 April 2010 |publisher=Fmi.fi}}</ref>

Winters in Helsinki are significantly warmer than in the north of Finland, and the snow season in the capital is much shorter due to its location in the extreme south of Finland and the [[urban heat island]] effect. Temperatures below {{convert|-20|C|F}} occur only a few times a year. However, due to the latitude, the days around the [[winter solstice]] are 5 hours and 48 minutes long, with the sun very low (at noon the sun is just over 6 degrees in the sky), and the cloudy weather at this time of year exacerbates the darkness. Conversely, Helsinki enjoys long days in summer, with 18 hours and 57 minutes of daylight around the [[summer solstice]].<ref>{{cite web |last=Tukiainen |first=Matti |title=Helsinki, Finland&nbsp;– Sunrise, sunset, dawn and dusk times around the World! |url=http://www.gaisma.com/en/location/helsinki.html |access-date=11 February 2011 |website=Gaisma}}</ref>

The average maximum temperature from June to August is around {{convert|19|to|22|C|F}}. Due to the sea effect, especially on hot summer days, daytime temperatures are slightly cooler and nighttime temperatures higher than further inland. The highest temperature recorded in the city was {{convert|33.2|C}} on 28 July 2019 at the [[Kaisaniemi]] weather station,<ref>{{cite web |last=<!--Not stated--> |date=28 July 2019 |title=Taulukkotilasto: Helsinki Kaisaniemi |url=https://kilotavu.com/asema-taulukko.php?asema=100971 |access-date=28 July 2019 |website=kilotavu.com |publisher=Finnish Meteorological Institute}}</ref> breaking the previous record of {{convert|33.1|C}} set in July 1945 at the [[Ilmala]] weather station.<ref name="Suomen Maakuntien Ilmasto">{{cite web |url=https://helda.helsinki.fi/bitstream/handle/10138/15734/2009nro8.pdf?sequence=1&isAllowed=y |title=Suomen Makkuntien Ilmasto |editor-last1=Kersalo |editor-first1=Juha |editor-last2=Pirinen |editor-first2=Pentti |publisher=Finnish Meteorological Institute |date=2009 |location=Helsinki |access-date=11 August 2021 }}</ref> The lowest temperature recorded in the city was {{convert|-34.3|C|F|abbr=on}} on 10 January 1987, although an unofficial low of {{convert|-35|C|0|abbr=on}} was recorded in December 1876.<ref name="Helsinki climate table">{{cite web |title=Helsinki Kaisaniemi - Taulukkotilasto |url=https://kilotavu.com/asema-taulukko.php?asema=100971 |website=kilotavu.com}}</ref> [[Helsinki Airport]] (in Vantaa, 17&nbsp;km north of Helsinki city centre) recorded a maximum temperature of {{convert|33.7|C}} on 29 July 2010 and a minimum of {{convert|-35.9|C|0|abbr=on}} on 9 January 1987. Precipitation comes from frontal passages and thunderstorms. Thunderstorms are most common in summer.

{{Weather box
|location = Central Helsinki ([[Kaisaniemi]]) 1991–2020 normals, records 1844–present
|metric first = Yes
|single line = Yes
|Jan record high C = 8.5
|Feb record high C = 10.3
|Mar record high C = 15.1
|Apr record high C = 21.9
|May record high C = 27.6
|Jun record high C = 30.9
|Jul record high C = 33.2
|Aug record high C = 31.2
|Sep record high C = 26.2
|Oct record high C = 17.6
|Nov record high C = 14.3
|Dec record high C = 10.5
|year record high C = 33.2
|Jan avg record high C = 4.7
|Feb avg record high C = 4.6
|Mar avg record high C = 8.4
|Apr avg record high C = 16.1
|May avg record high C = 22.5
|Jun avg record high C = 24.9
|Jul avg record high C = 27.1
|Aug avg record high C = 25.4
|Sep avg record high C = 20.4
|Oct avg record high C = 14.6
|Nov avg record high C = 9.5
|Dec avg record high C = 6.0
|year avg record high C = 27.9
|Jan high C = −0.7
|Feb high C = −1.3
|Mar high C = 2.3
|Apr high C = 8.1
|May high C = 14.6
|Jun high C = 18.8
|Jul high C = 21.9
|Aug high C = 20.5
|Sep high C = 15.4
|Oct high C = 9.2
|Nov high C = 4.4
|Dec high C = 1.4
|year high C = 9.6
|Jan mean C = −3.1
|Feb mean C = −3.8
|Mar mean C = −0.7
|Apr mean C = 4.4
|May mean C = 10.4
|Jun mean C = 14.9
|Jul mean C = 18.1
|Aug mean C = 16.9
|Sep mean C = 12.3
|Oct mean C = 6.6
|Nov mean C = 2.4
|Dec mean C = −0.7
|year mean C = 6.5
|Jan low C = −5.6
|Feb low C = −6.3
|Mar low C = −3.6
|Apr low C = 1.1
|May low C = 6.4
|Jun low C = 11.2
|Jul low C = 14.5
|Aug low C = 13.5
|Sep low C = 9.3
|Oct low C = 4.2
|Nov low C = 0.4
|Dec low C = −2.9
|year low C = 3.5
|Jan avg record low C = -17.7
|Feb avg record low C = -16.9
|Mar avg record low C = -11.9
|Apr avg record low C = -4.4
|May avg record low C = 0.7
|Jun avg record low C = 6.0
|Jul avg record low C = 10.2
|Aug avg record low C = 8.3
|Sep avg record low C = 2.5
|Oct avg record low C = -3.9
|Nov avg record low C = -7.4
|Dec avg record low C = -12.8
|year avg record low C = -20.6
|Jan record low C = -34.4
|Feb record low C = -33.0
|Mar record low C = -31.3
|Apr record low C = -19.8
|May record low C = -7.0
|Jun record low C = -0.5
|Jul record low C = 4.9
|Aug record low C = 2.1
|Sep record low C = -4.5
|Oct record low C = -13.9
|Nov record low C = -25.5
|Dec record low C = -35.0
|year record low C = -35.0
| precipitation colour = green
| Jan precipitation mm = 53
| Feb precipitation mm = 38
| Mar precipitation mm = 34
| Apr precipitation mm = 34
| May precipitation mm = 38
| Jun precipitation mm = 60
| Jul precipitation mm = 57
| Aug precipitation mm = 81
| Sep precipitation mm = 56
| Oct precipitation mm = 73
| Nov precipitation mm = 69
| Dec precipitation mm = 58
| year precipitation mm = 653
| Jan rain days = 19
| Feb rain days = 16
| Mar rain days = 13
| Apr rain days = 12
| May rain days = 11
| Jun rain days = 14
| Jul rain days = 12
| Aug rain days = 13
| Sep rain days = 14
| Oct rain days = 16
| Nov rain days = 17
| Dec rain days = 19
| year rain days = 
| unit rain days = 0.1 mm
|Jan sun = 37.2
|Feb sun = 70.6
|Mar sun = 139.5
|Apr sun = 195.0
|May sun = 285.2
|Jun sun = 297.0
|Jul sun = 291.4
|Aug sun = 238.7
|Sep sun = 150.0
|Oct sun = 93.0
|Nov sun = 36.0
|Dec sun = 27.9
|Jand sun = 1.2
|Febd sun = 2.5
|Mard sun = 4.5
|Aprd sun = 6.5
|Mayd sun = 9.2
|Jund sun = 9.9
|Juld sun = 9.4
|Augd sun = 7.7
|Sepd sun = 5
|Octd sun = 3
|Novd sun = 1.2
|Decd sun = 0.9
|Jan light = 6.8
|Feb light = 9.2
|Mar light = 11.8
|Apr light = 14.6
|May light = 17.2
|Jun light = 18.8
|Jul light = 18.0
|Aug light = 15.6
|Sep light = 12.9
|Oct light = 10.1
|Nov light = 7.5
|Dec light = 6.0
|Jan percentsun = 18
|Feb percentsun = 27
|Mar percentsun = 38
|Apr percentsun = 45
|May percentsun = 53
|Jun percentsun = 53
|Jul percentsun = 52
|Aug percentsun = 49
|Sep percentsun = 39
|Oct percentsun = 30
|Nov percentsun = 16
|Dec percentsun = 15
|Jan uv = 0
|Feb uv = 0
|Mar uv = 1
|Apr uv = 3
|May uv = 4
|Jun uv = 5
|Jul uv = 5
|Aug uv = 4
|Sep uv = 3
|Oct uv = 1
|Nov uv = 0
|Dec uv = 0
| source 1 = FMI climatological normals for Finland 1991&ndash;2020,<ref name="FMI">{{cite web |title=FMI normals 1991-2020 |url=https://www.ilmatieteenlaitos.fi/ilmastollinen-vertailukausi |access-date=7 October 2021|publisher=fmi.fi}}</ref> record highs and lows<ref name="FMI data">{{cite web |title=FMI data |url=http://suja.kapsi.fi/fmi-tilastot.php?taulukkomoodi=true |access-date=25 September 2020 |publisher=FMI}}</ref>
| date = September 2020
|source 2 = Weather Atlas (sun data)<ref name="Weather Atlas">{{cite web |url=https://www.weather-atlas.com/en/finland/helsinki-climate |title=Helsinki, Finland - Monthly weather forecast and Climate data |publisher=Weather Atlas |access-date=22 May 2023 }}</ref>}}

{{Weather box
| location = Helsinki Kumpula (1991–2020 normals)
| metric first = Yes
| single line = Yes
|Jan sun = 35
|Feb sun = 71
|Mar sun = 146
|Apr sun = 203
|May sun = 296
|Jun sun = 278
|Jul sun = 308
|Aug sun = 248
|Sep sun = 160
|Oct sun = 89
|Nov sun = 34
|Dec sun = 23
|year sun = 1890
| source 1 = https://ilmatieteenlaitos.fi/1991-2020-auringonpaiste-ja-sateilytilastot
}}

{{Weather box
| location = [[Helsinki Airport]] ([[Vantaa]]) 1991–2020 normals, records 1952–present
| metric first = Yes
| single line = Yes
| collapsed = y
| Jan record high C = 8.2
| Feb record high C = 10.0
| Mar record high C = 17.5
| Apr record high C = 24.0
| May record high C = 29.6
| Jun record high C = 31.4
| Jul record high C = 33.7
| Aug record high C = 31.5
| Sep record high C = 27.7
| Oct record high C = 18.2
| Nov record high C = 13.4
| Dec record high C = 10.8
| year record high C = 
| Jan high C = −1.8
| Feb high C = −2
| Mar high C = 2.2
| Apr high C = 9.1
| May high C = 16.0
| Jun high C = 20.1
| Jul high C = 23.0
| Aug high C = 21.2
| Sep high C = 15.7
| Oct high C = 8.6
| Nov high C = 3.4
| Dec high C = 0.4
| year high C = 9.7
| Jan mean C = −4.3
| Feb mean C = −4.9
| Mar mean C = −1.4
| Apr mean C = 4.5
| May mean C = 10.9
| Jun mean C = 15.3
| Jul mean C = 18.3
| Aug mean C = 16.6
| Sep mean C = 11.6
| Oct mean C = 5.8
| Nov mean C = 1.4
| Dec mean C = −1.9
| year mean C = 6.0
| Jan low C = -7.1
| Feb low C = -7.9
| Mar low C = −5
| Apr low C = 0.1
| May low C = 5.3
| Jun low C = 10.2
| Jul low C = 13.3
| Aug low C = 12.0
| Sep low C = 7.7
| Oct low C = 2.8
| Nov low C = −1
| Dec low C = −4.4
| year low C = 2.2
| Jan record low C = −35.9
| Feb record low C = −33.3
| Mar record low C = −27.2
| Apr record low C = −16.9
| May record low C = −5.6
| Jun record low C = −0.6
| Jul record low C = 3.7
| Aug record low C = 0.4
| Sep record low C = −7.3
| Oct record low C = −14.5
| Nov record low C = −20.8
| Dec record low C = −32.3
| year record low C = 
| precipitation colour = green
| Jan precipitation mm = 54
| Feb precipitation mm = 41
| Mar precipitation mm = 34
| Apr precipitation mm = 36
| May precipitation mm = 39
| Jun precipitation mm = 64
| Jul precipitation mm = 64
| Aug precipitation mm = 78
| Sep precipitation mm = 62
| Oct precipitation mm = 79
| Nov precipitation mm = 70
| Dec precipitation mm = 62
| year precipitation mm = 
| Jan rain days = 24
| Feb rain days = 21
| Mar rain days = 16
| Apr rain days = 12
| May rain days = 12
| Jun rain days = 14
| Jul rain days = 13
| Aug rain days = 15
| Sep rain days = 15
| Oct rain days = 18
| Nov rain days = 21
| Dec rain days = 24
| year rain days = 
| unit rain days = 0.1 mm
| Jan sun = 38
| Feb sun = 74
| Mar sun = 131
| Apr sun = 196
| May sun = 275
| Jun sun = 266
| Jul sun = 291
| Aug sun = 219
| Sep sun = 143
| Oct sun = 84
| Nov sun = 37
| Dec sun = 26
| year sun = 
| Jan percentsun = 17
| Feb percentsun = 28
| Mar percentsun = 38
| Apr percentsun = 43
| May percentsun = 54
| Jun percentsun = 52
| Jul percentsun = 52
| Aug percentsun = 48
| Sep percentsun = 39
| Oct percentsun = 30
| Nov percentsun = 17
| Dec percentsun = 15
| year percentsun = 
| Jan snow days = 26.4
| Feb snow days = 25.7
| Mar snow days = 25.2
| Apr snow days = 8.4
| May snow days = 0.4
| Jun snow days = 0.0
| Jul snow days = 0.0
| Aug snow days = 0.0
| Sep snow days = 0.1
| Oct snow days = 2.5
| Nov snow days = 13.6
| Dec snow days = 19.3
| year snow days = 121.6
| source 1 = FMI climatological normals for Finland 1991-2020<ref name="FMI"/> Weatheronline.co.uk<ref name="Weatheronline.co.uk">{{cite web|url=https://www.weatheronline.co.uk/weather/maps/city?FMM=1&FYY=1991&LMM=12&LYY=2020&WMO=02974&CONT=euro&REGION=0004&LAND=FI&ART=SNT&R=0&NOREGION=1&LEVEL=162&LANG=en&MOD=tab|title=Weatheronline.co.uk}}</ref>
| source 2 = record highs and lows<ref name="FMI open data">{{cite web |title=FMI open data |url=https://www.ilmatieteenlaitos.fi/ilmastollinen-vertailukausi |access-date=19 May 2025 |publisher=FMI}}</ref>
| date = October 2021
| source = 
| Jul avg record low C = 8.6
| Aug avg record low C = 6.1
| Jun avg record low C = 4.1
| Sep avg record low C = 0.4
| May avg record low C = -1.2
| Oct avg record low C = -5.6
| Apr avg record low C = -6.2
| Nov avg record low C = -10.0
| Mar avg record low C = -14.8
| Dec avg record low C = -15.7
| Jan avg record low C = -20.5
| Feb avg record low C = -19.9
| year avg record low C = -23.9
| Jan avg record high C = 4.3
| Feb avg record high C = 4.2
| Mar avg record high C = 9.3
| Apr avg record high C = 18.1
| May avg record high C = 24.9
| Jun avg record high C = 26.6
| Jul avg record high C = 28.7
| Aug avg record high C = 27.2
| Sep avg record high C = 21.6
| Oct avg record high C = 14.8
| Nov avg record high C = 9.1
| Dec avg record high C = 5.4
| year avg record high C = 29.7
}}