Editing Aachen (section)

=== Climate ===
As the westernmost city in Germany<ref name="Munro 1995">{{harvnb|Munro|1995|p=1}}.</ref> (and close to the Low Countries), Aachen and the surrounding area belongs to a [[Temperate climate|temperate]] [[Oceanic climate|climate zone]] ([[Köppen climate classification|Cfb]]), with humid weather, mild winters, and warm summers. Because of its location north of the [[Eifel]] and the [[High Fens]] and its subsequent prevailing westerly weather patterns, rainfall in Aachen (on average 805&nbsp;mm/year) is comparatively higher than, for example, in [[Bonn]] (with 669&nbsp;mm/year). Another factor in the local weather forces of Aachen is the occurrence of [[Foehn winds]] on the southerly air currents, which results from the city's geographic location on the northern edge of the Eifel.

Because the city is surrounded by hills, it suffers from [[inversion (meteorology)|inversion-related]] smog. Some areas of the city have become [[urban heat island]]s as a result of poor heat exchange, both because of the area's natural geography and from human activity. The city's numerous cold air corridors, which are slated to remain as free as possible from new construction, therefore play an important role in the urban climate of Aachen.<ref>{{harvnb|Aachen Department of Environment|2013}}.</ref>

The January average is
{{convert|3.0|°C|0|abbr=on}}, while the July average is {{convert|18.5|°C|0|abbr=on}}. Precipitation is almost evenly spread throughout the year.

The city's oceanic climate provides comparably mild winters: While Aachen falls within the coldest extents covered by [[Hardiness zone|USDA plant hardiness zone]] 8b in the 1991–2020 period, having an average yearly minimum of -9.22&nbsp;°C (15.4&nbsp;°F), the Canadian city of [[Regina, Saskatchewan]] which is located at a similar latitude but at the heart of the North American landmass, far away from the sea's moderating effects, is classified as being in zone 3a.<ref>{{Cite web |last=Government of Canada |first=Natural Resources Canada |title=Canada's Plant Hardiness Site |url=http://planthardiness.gc.ca/?m=1&lang=en |access-date=2023-11-14 |website=planthardiness.gc.ca}}</ref>

In the 1991–2020 period, the last freeze (at 2 m above ground) of spring occurred on April 28th and the first fall freeze on October 13th, on average.<ref>{{Cite web |title=Wetter und Klima - Deutscher Wetterdienst - Leistungen - Frühester / spätester Frost |url=https://www.dwd.de/DE/leistungen/frost_termine/frosttermine.html#buehneTop |access-date=2024-09-25 |website=www.dwd.de}}</ref>

The Aachen weather station has recorded the following extreme values:<ref name=sklima/>
* Highest Temperature {{convert|38.6|C|F}} on [[2019_European_heatwaves#Germany|25 July 2019]].
* Warmest Minimum {{convert|24.5|C|F}} on 29 July 1947.
* Coldest Maximum {{convert|-12.8|C|F}} on 22 January 1940.
* Lowest Temperature {{convert|-20.4|C|F}} on 11 January 1945.<ref name=wetterzentrale/>
* Highest Daily Precipitation {{convert|98.7|mm|in|abbr=on}} on 14 July 2021.
* Wettest Month {{convert|232.2|mm|in|abbr=on}} in July 2021.
* Wettest Year {{convert|1121.1|mm|in|abbr=on}} in 1966.
* Driest Year {{convert|530.5|mm|in|abbr=on}} in 1959.
* Earliest Snowfall: 4 November 1941.
* Latest Snowfall: 30 April 1938.
* Longest annual sunshine: 2,128.4 hours in 2003.
* Shortest annual sunshine: 1,277.4 hours in 1981.

{{Weather box|width=auto
|location = Aachen (1991–2020 normals, extremes 1891–present{{efn|Temperature data for Aachen have been recorded since 1891. The weather station data used from 1 January 1891 to 31 March 2011 came from Aachen weather station, and temperature data from 1 April 2011 to the present are from {{ill|Aachen-Orsbach|de|Orsbach}}.}})	
|metric first = Y	
|single line = Y
|Jan record high C = 16.2
|Feb record high C = 20.5
|Mar record high C = 24.5
|Apr record high C = 30.0
|May record high C = 34.2
|Jun record high C = 36.6
|Jul record high C = 38.6
|Aug record high C = 37.2
|Sep record high C = 34.3
|Oct record high C = 26.9
|Nov record high C = 22.1
|Dec record high C = 17.6
|year record high C = 38.6
|Jan avg record high C = 12.5
|Feb avg record high C = 13.9
|Mar avg record high C = 18.5
|Apr avg record high C = 23.3
|May avg record high C = 26.8
|Jun avg record high C = 30.4
|Jul avg record high C = 32.4
|Aug avg record high C = 31.9
|Sep avg record high C = 27.0
|Oct avg record high C = 22.5
|Nov avg record high C = 16.5
|Dec avg record high C = 12.7
|year avg record high C = 34.1
|Jan high C = 5.7
|Feb high C = 6.8
|Mar high C = 10.6
|Apr high C = 14.7
|May high C = 18.5
|Jun high C = 21.4
|Jul high C = 23.7
|Aug high C = 23.3
|Sep high C = 19.4
|Oct high C = 14.8
|Nov high C = 9.4
|Dec high C = 5.6
|year high C = 14.5
|Jan mean C = 3.2
|Feb mean C = 3.8
|Mar mean C = 6.6
|Apr mean C = 10.0
|May mean C = 13.8
|Jun mean C = 16.6
|Jul mean C = 18.7
|Aug mean C = 18.3
|Sep mean C = 14.8
|Oct mean C = 10.8
|Nov mean C = 6.7
|Dec mean C = 3.3
|year mean C = 10.5
|Jan low C = 0.8
|Feb low C = 1.2
|Mar low C = 3.4
|Apr low C = 5.8
|May low C = 9.3
|Jun low C = 12.0
|Jul low C = 14.4
|Aug low C = 14.0
|Sep low C = 11.2
|Oct low C = 7.7
|Nov low C = 4.4
|Dec low C = 1.2
|year low C = 7.1
|Jan avg record low C = -6.9
|Feb avg record low C = -5.8
|Mar avg record low C = -2.9
|Apr avg record low C = -0.6
|May avg record low C = 3.0
|Jun avg record low C = 6.8
|Jul avg record low C = 9.4
|Aug avg record low C = 9.4
|Sep avg record low C = 6.2
|Oct avg record low C = 1.2
|Nov avg record low C = -1.9
|Dec avg record low C = -5.1
|year avg record low C = -9.2
|Jan record low C = -20.4
|Feb record low C = -20.2
|Mar record low C = -11.9
|Apr record low C = -4.8
|May record low C = -1.3
|Jun record low C = 1.8
|Jul record low C = 5.8
|Aug record low C = 3.4
|Sep record low C = 0.0
|Oct record low C = -5.7
|Nov record low C = -8.9
|Dec record low C = -16.5
|year record low C = -20.4
|precipitation colour = green	
|Jan precipitation mm = 64.3
|Feb precipitation mm = 63.4
|Mar precipitation mm = 59.3
|Apr precipitation mm = 53.5
|May precipitation mm = 65.0
|Jun precipitation mm = 70.0
|Jul precipitation mm = 79.0
|Aug precipitation mm = 80.6
|Sep precipitation mm = 68.1
|Oct precipitation mm = 66.1
|Nov precipitation mm = 66.6
|Dec precipitation mm = 74.4
|year precipitation mm = 811.4
|unit precipitation days = 0.1 mm	
|Jan precipitation days = 17.0
|Feb precipitation days = 16.5
|Mar precipitation days = 16.4
|Apr precipitation days = 13.5
|May precipitation days = 15.9
|Jun precipitation days = 14.6
|Jul precipitation days = 15.3
|Aug precipitation days = 14.4
|Sep precipitation days = 14.1
|Oct precipitation days = 15.1
|Nov precipitation days = 18.2
|Dec precipitation days = 18.2
|year precipitation days = 189.6
|Jan snow depth cm = 4.6
|Feb snow depth cm = 5.4
|Mar snow depth cm = 1.7
|Apr snow depth cm = 0.4
|May snow depth cm = 0
|Jun snow depth cm = 0
|Jul snow depth cm = 0
|Aug snow depth cm = 0
|Sep snow depth cm = 0
|Oct snow depth cm = 0
|Nov snow depth cm = 0.7
|Dec snow depth cm = 4.3
|year snow depth cm = 9.8
|unit snow days = 1.0 cm
|Jan snow days = 5.5
|Feb snow days = 5.1
|Mar snow days = 1.2
|Apr snow days = 0.1
|May snow days = 0
|Jun snow days = 0
|Jul snow days = 0
|Aug snow days = 0
|Sep snow days = 0
|Oct snow days = 0
|Nov snow days = 1.1
|Dec snow days = 3.8
|year snow days = 17.1
|humidity colour = green
|Jan humidity = 82.1	
|Feb humidity = 80.1
|Mar humidity = 74.9
|Apr humidity = 68.9
|May humidity = 70.3
|Jun humidity = 70.5
|Jul humidity = 70.7
|Aug humidity = 72.1
|Sep humidity = 77.4
|Oct humidity = 80.7
|Nov humidity = 83.7
|Dec humidity = 84.8
|year humidity = 76.4
|Jan sun = 68.3
|Feb sun = 75.0
|Mar sun = 126.2
|Apr sun = 168.7
|May sun = 194.9
|Jun sun = 207.9
|Jul sun = 208.1
|Aug sun = 196.9
|Sep sun = 151.3
|Oct sun = 121.5
|Nov sun = 68.0
|Dec sun = 52.5
|year sun = 1634.3
|source 1 = [[NOAA]]<ref name=NOAA>{{cite web
|archive-url = https://web.archive.org/web/20230914163046/https://www.nodc.noaa.gov/archive/arc0216/0253808/1.1/data/0-data/Region-6-WMO-Normals-9120/Germany/CSV/Aachen_10501.csv
|archive-date = 14 September 2023
|url = https://www.nodc.noaa.gov/archive/arc0216/0253808/1.1/data/0-data/Region-6-WMO-Normals-9120/Germany/CSV/Aachen_10501.csv
|title = Aachen Climate Normals 1991–2020
|publisher = [[National Oceanic and Atmospheric Administration]]
|access-date = 15 September 2023}}</ref>
|source 2 = Data derived from [[Deutscher Wetterdienst]]<ref>{{harvnb|Federal Ministry of Transport, Building, and Urban Development|2013}}.</ref><ref name=wetterzentrale>
{{cite web
|url = https://www.wetterzentrale.de/extremes_mon.php?station=3&maand=1&country=1&order=1&extreem=X_TX
|title = Extremwertanalyse der DWD-Stationen, Tagesmaxima, Dekadenrekorde, usw.
|publisher = DWD
|language = de
|access-date = 9 December 2023}}</ref><ref>
{{cite web
|url = https://www.wetterzentrale.de/extremes_mon.php?station=15000&maand=1&country=1&order=1&extreem=X_TX
|title = Extremwertanalyse der DWD-Stationen, Tagesmaxima, Dekadenrekorde, usw.
|publisher = DWD
|language = de
|access-date = 10 December 2023}}</ref><ref name=sklima>{{cite web 
|url = http://sklima.de/datenbank_auswertung.php?tab=2
|title = Monatsauswertung 
|website = sklima.de 
|publisher = SKlima 
|language = de 
|access-date = 27 October 2024}}</ref>
| date = May 2013
}}