Editing Decorah, Iowa (section)

==Geography==
Decorah is located approximately {{convert|15|mi|km}} south of the [[Minnesota]]-Iowa border. It is the northernmost major community located along [[U.S. Route 52 in Iowa]]. According to the [[United States Census Bureau]], the city has a total area of {{convert|7.04|sqmi|sqkm|2}}, of which {{convert|7.01|sqmi|sqkm|2}} is land and {{convert|0.03|sqmi|sqkm|2}} is water.<ref name="Gazetteer files">{{cite web |title=US Gazetteer files 2010 |url=https://www.census.gov/geo/www/gazetteer/files/Gaz_places_national.txt |publisher=[[United States Census Bureau]] |access-date=2012-05-11 |url-status=dead |archive-url=https://web.archive.org/web/20120125061959/http://www.census.gov/geo/www/gazetteer/files/Gaz_places_national.txt |archive-date=2012-01-25 }}</ref> Decorah is located in and on the bluffs of the [[Upper Iowa River]] valley; the river flows through the city en route to its confluence with the [[Upper Mississippi River]].<ref name=":0" /> The river is faced by steep bluffs, characteristic of the [[Driftless Area]].
{{wide image|Decorah, Iowa.jpg|400px|[[U.S. Route 52|US-52]] and [[Iowa Highway 9|IA-9]] junction on the southwestern part of town|100%|center
|alt=Decorah, Iowa US-52 and IA-9 junction on the southwestern part of town}}

===Impact crater===
{{main|Decorah crater}}
About 470 million years ago, a meteorite as big as a city block smashed into what is now Decorah, supporting a theory that a giant space rock broke up and bombarded Earth just as early life began flourishing in the oceans.<ref name="Crater found">{{cite news|first=Brian|last=Vastag|title=Crater found in Iowa points to asteroid break-up 470 million years ago |url=https://www.washingtonpost.com/national/health-science/crater-found-in-iowa-points-to-asteroid-break-up-470-million-years-ago/2013/02/18/545131f8-76d5-11e2-aa12-e6cf1d31106b_story.html|newspaper=The Washington Post|date=2013-02-18}}</ref>

The impact dug a crater nearly four miles wide that now lies beneath the town, said Bevan French, one of the world's foremost crater hunters and an adjunct scientist at the National Museum of Natural History.<ref name="Crater found"/>

The Decorah crater lay undiscovered until recently because almost none of it is above ground. Instead, it is filled by an unusual shale that formed after an ancient seaway sluiced into the crater, depositing sediment and an array of bizarre sea creatures that hardened into fossils.<ref name="Crater found"/> One such creature is ''[[Pentecopterus decorahensis]]'', which was named for the city.<ref name="BMC-20150901">{{cite journal |last1=Lamsdell |first1=James C. |last2=Briggs |first2=Derek E. G. |last3=Liu |first3=Huaibao |last4=Witzke |first4=Brian J. |last5=McKay |first5=Robert M. |title=The oldest described eurypterid: a giant Middle Ordovician (Darriwilian) megalograptid from the Winneshiek Lagerstätte of Iowa |date=1 September 2015 |journal=[[BMC Evolutionary Biology]] |volume=15 |pages=169 |doi=10.1186/s12862-015-0443-9 |pmid=26324341 |pmc=4556007 |doi-access=free }}</ref>

===Climate===
{{Weather box 
| location = Decorah, Iowa (1991–2020 normals, extremes 1893–present)
| single line = Y
| collapsed = yes
| Jan record high F = 62
| Feb record high F = 74
| Mar record high F = 85
| Apr record high F = 93
| May record high F = 102
| Jun record high F = 105
| Jul record high F = 111
| Aug record high F = 105
| Sep record high F = 100
| Oct record high F = 94
| Nov record high F = 79
| Dec record high F = 69
| year record high F = 111

|Jan avg record high F = 45.4
|Feb avg record high F = 49.6
|Mar avg record high F = 67.2
|Apr avg record high F = 80.3
|May avg record high F = 87.2
|Jun avg record high F = 91.5
|Jul avg record high F = 92.2
|Aug avg record high F = 90.8
|Sep avg record high F = 88.3
|Oct avg record high F = 81.6
|Nov avg record high F = 64.8
|Dec avg record high F = 49.2
|year avg record high F = 94.0

| Jan high F = 27.7
| Feb high F = 32.8
| Mar high F = 46.2
| Apr high F = 61.3
| May high F = 72.5
| Jun high F = 81.4
| Jul high F = 84.4
| Aug high F = 82.7
| Sep high F = 76.4
| Oct high F = 63.2
| Nov high F = 46.6
| Dec high F = 32.9
| year high F = 59.0
| Jan mean F = 19.0
| Feb mean F = 23.4
| Mar mean F = 36.0
| Apr mean F = 49.3
| May mean F = 60.5
| Jun mean F = 70.0
| Jul mean F = 73.5
| Aug mean F = 71.7
| Sep mean F = 64.4
| Oct mean F = 51.8
| Nov mean F = 37.5
| Dec mean F = 25.2
| year mean F = 48.5
| Jan low F = 10.4
| Feb low F = 14.0
| Mar low F = 25.9
| Apr low F = 37.3
| May low F = 48.4
| Jun low F = 58.6
| Jul low F = 62.6
| Aug low F = 60.7
| Sep low F = 52.3
| Oct low F = 40.4
| Nov low F = 28.4
| Dec low F = 17.4
| year low F = 38.0

|Jan avg record low F = -18.2
|Feb avg record low F = -12.3
|Mar avg record low F = 0.3
|Apr avg record low F = 19.7
|May avg record low F = 30.2
|Jun avg record low F = 42.3
|Jul avg record low F = 48.8
|Aug avg record low F = 46.8
|Sep avg record low F = 34.0
|Oct avg record low F = 21.8
|Nov avg record low F = 8.3
|Dec avg record low F = -8.4
|year avg record low F = -22.2

| Jan record low F = −43
| Feb record low F = −41
| Mar record low F = −33
| Apr record low F = 5
| May record low F = 20
| Jun record low F = 29
| Jul record low F = 38
| Aug record low F = 32
| Sep record low F = 18
| Oct record low F = -7
| Nov record low F = −16
| Dec record low F = −36
| year record low F = 
| precipitation colour = green
| Jan precipitation inch = 1.01
| Feb precipitation inch = 1.10
| Mar precipitation inch = 2.05
| Apr precipitation inch = 3.95
| May precipitation inch = 4.94
| Jun precipitation inch = 6.13
| Jul precipitation inch = 4.42
| Aug precipitation inch = 4.39
| Sep precipitation inch = 3.60
| Oct precipitation inch = 2.66
| Nov precipitation inch = 2.05
| Dec precipitation inch = 1.31
| year precipitation inch = 37.61
| Jan snow inch = 10.3
| Feb snow inch = 8.3
| Mar snow inch = 5.7
| Apr snow inch = 1.7
| May snow inch = 0.0
| Jun snow inch = 0.0
| Jul snow inch = 0.0
| Aug snow inch = 0.0
| Sep snow inch = 0.0
| Oct snow inch = 0.0
| Nov snow inch = 2.4
| Dec snow inch = 9.1
| year snow inch = 37.5
| unit precipitation days = 0.01 in
| Jan precipitation days = 7.5
| Feb precipitation days = 6.2
| Mar precipitation days = 8.0
| Apr precipitation days = 12.0
| May precipitation days = 13.4
| Jun precipitation days = 12.2
| Jul precipitation days = 9.9
| Aug precipitation days = 10.0
| Sep precipitation days = 9.3
| Oct precipitation days = 9.4
| Nov precipitation days = 7.6
| Dec precipitation days = 8.4
| year precipitation days = 113.9
| unit snow days = 0.1 in
| Jan snow days = 6.2
| Feb snow days = 5.2
| Mar snow days = 2.8
| Apr snow days = 1.0
| May snow days = 0.0
| Jun snow days = 0.0
| Jul snow days = 0.0
| Aug snow days = 0.0
| Sep snow days = 0.0
| Oct snow days = 0.0
| Nov snow days = 1.9
| Dec snow days = 6.2
| year snow days = 23.3
| source 1 = [[NOAA]]<ref name= nws >
{{cite web
| url = https://w2.weather.gov/climate/xmacis.php?wfo=arx
| title = NowData – NOAA Online Weather Data
| publisher = National Oceanic and Atmospheric Administration
| access-date = June 25, 2021}}</ref><ref name=NCEI>
{{cite web
| url = https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-monthly-1991-2020&startDate=0001-01-01&endDate=9996-12-31&stations=USC00132110&format=pdf
| title = Station: Decorah, IA
| work = U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020)
| publisher = National Oceanic and Atmospheric Administration
| access-date = June 25, 2021}}</ref>
}}