Editing Eureka, California (section)

== Geography ==

According to the [[United States Census Bureau]], the city has a total area of {{convert|14.5|sqmi|km2}}, of which {{convert|9.4|sqmi|km2}} is land and {{convert|5.1|sqmi|km2}} or 35.07% is water.

Eureka is situated within California's [[Redwood Empire]] region which includes Pacific Ocean coast, [[Humboldt Bay (United States)|Humboldt Bay]], and several rivers in addition to [[Redwood National and State Parks]] and [[Humboldt Redwoods State Park]]. The location of Eureka on [[U.S. Route 101|U.S. 101]] is {{convert|283|mi}} north of San Francisco and {{convert|315|mi|abbr=on}} northwest of [[Sacramento]].

The city marina is on one of three islands at a narrow point on the {{convert|13|mi|km|adj=mid|-long}} bay and increases in elevation slightly as it spreads north, south, and especially to the east. The city gently encroaches at least two miles ({{convert|2|mi|abbr=out|disp=output only}}) eastward into primarily [[Sequoia sempervirens|Redwood]] and [[Douglas-fir]] second growth forests. The city has a traditional grid that generally radiates toward the points of the compass. Most post-1970 houses were built in formerly clear cut forested areas.

The transition between the official city limits and smaller unincorporated areas is mostly not discernible. Eastern areas including secluded developments on a golf course among or in close proximity to extensive second-growth forest have more recently developed. These new houses were built as a result of the Eureka Community Plan of 1995 in attempt to bring locals close to centers of recreation and encourage community interaction.<ref>{{cite web|title=Eureka Community Plan|url=http://www.humboldtgov.org/DocumentCenter/Home/View/284|website=Humboldt County|access-date=September 12, 2017|archive-date=April 24, 2015|archive-url=https://web.archive.org/web/20150424175143/http://humboldtgov.org/DocumentCenter/Home/View/284|url-status=dead}}</ref> The city then gives way to hills and mountains of the rugged coast range, which quickly exceed {{convert|2000|ft|m}} in elevation.

Eureka is more or less on the same latitude as [[Atlantic Ocean|Atlantic]] cities [[New York City]] and [[Porto]] in [[Portugal]] along with the [[Mediterranean Sea|Mediterranean]] city of [[Naples]] in [[Italy]],<ref>{{cite web|url=https://www.google.com/maps|title=Google Maps|accessdate=July 26, 2022}}</ref> all of whom have much warmer summers in spite of also being on coastlines. By comparison, New York City's climate is far more continental than Eureka's, despite both cities being located around the 41st parallel and near the ocean.

=== Climate ===
[[File:Monthly Climate Normals (1991-2020) - Eureka Area, CA(ThreadEx).svg|thumb|right|Climate chart for Eureka]]
Eureka has a mild, temperate cool-summer [[mediterranean climate]] ([[Köppen climate classification]]: ''Csb''). Due to the influence of the [[Pacific Ocean]] and being on the shoreline of the cold-water [[Humboldt Bay]], its temperatures are cooler than those of a typical mediterranean climate. Winters are mild and rainy, and summers are mild, cool, and dry. The average high in December, the coolest month, is {{cvt|55.0|°F|°C}}, while the average high temperature in August, the warmest month, is {{cvt|64.3|°F|°C}}, which is very mild and cool, respectively, for an area at such a southerly latitude. Eureka's average summer temperatures are much cooler than&nbsp;[[New York City]] and&nbsp;[[Istanbul]]&nbsp;which lie on the same latitude (and its average winter temperatures are also milder than those two cities); and are similar to those of&nbsp;[[Southeast Alaska]], [[Scotland]] or [[Tierra del Fuego]]&nbsp;in southern [[Argentina]] and [[Chile]], which lie well above the 50th parallel.

The seasonal temperature variation is very small; the difference between the August average of {{cvt|58.5|F|C}} and the December average of {{cvt|47.8|F|C}} is only {{cvt|10.7|F-change|C-change}}, about equal to the [[diurnal temperature variation]]. Eureka is unique among mid-latitude climates in the northern hemisphere in that in more than 135 years of recorded temperatures, February has measured a warmer absolute maximum temperature than both the two high summer months of July and August. The absolute maximum temperature of July is merely {{cvt|77|F|C}} in spite of the high sun strength. The two warmest nights measured in Eureka were both during winter, as January 18, 1981, recorded a low of {{cvt|63|F|C}}, tying a February 26, 1980, record.<ref>{{cite web|url=https://www.weather.gov/eka/ekarecords|title=NWS Eureka - Climate Record Extremes|publisher=[[National Weather Service]]|accessdate=June 3, 2022}}</ref><ref name=Eureka19912020>{{cite web|url=https://www.weather.gov/wrh/climate?wfo=eka|title=Climate data for Eureka|publisher=[[National Weather Service]]|accessdate=June 3, 2022}}</ref>

In addition, Eureka has a very short and milder range of temperatures compared to most of the [[contiguous US]], with the all-time highest and lowest temperatures recorded in Eureka being only {{cvt|87|°F|°C|1}} on October 26, 1993, September 2, 2017,<ref>{{Cite web |url=http://w2.weather.gov/climate/getclimate.php?wfo=eka |title=Archived copy |access-date=September 3, 2017 |archive-url=https://web.archive.org/web/20170917194051/http://w2.weather.gov/climate/getclimate.php?wfo=eka |archive-date=September 17, 2017 |url-status=dead }}</ref> and September 28, 2020,<ref>{{Cite web|url=https://w2.weather.gov/climate/getclimate.php?wfo=eka|title = Climate}}</ref> and {{cvt|20|°F|°C|1}} on January 14, 1888, respectively. On average, the highest temperature seen throughout the entire year is only {{cvt|79|°F|1}}, one of the coolest in the contiguous US, while on average the lowest temperature seen in the year (most often occurring at night) is only a similarly moderate {{cvt|29|°F|1}}, yielding a very short and mild temperature range of about {{convert|50|F-change|C-change}} throughout the year. Additionally, Eureka remains the only city on the [[West Coast of the United States|West Coast]] of the continental United States to have never recorded a temperature of {{cvt|90|°F|1}}.{{Citation needed|date=September 2024}}

Temperatures drop to freezing or below only on a few nights per year, and daytime temperatures for these days are typically mild temperatures ranging between {{cvt|43|-|58|°F|1}}. Eureka has never recorded an ice day, with the coldest daytime maximum being {{convert|34|F|C}} in 1990.<ref name=Eureka19912020/> Between 1991 and 2020, the coldest daytime high of the year was {{convert|45|F|C}} and the warmest night averaged {{convert|59|F|C}}.<ref name=Eureka19912020/> [[National Oceanic and Atmospheric Administration|NOAA]]'s weather station averages indicate only {{cvt|0.18|in|mm|1}} of rainfall in July, which is well within the mediterranean range, only with rainier winters, cooler and milder air than a typical mediterranean climate. Winter temperatures instead are similar to many climates found in Southern Europe from which basin the climate type is named.<!-- Bari, Marseille, Porto, et cetera. Servizio Meteorologico, Météo France and IPMA stations cited on their respective Wikipedia pages concur. -->

The area experiences coastal fog throughout the year, especially during summer on the coast when temperatures in the city remain consistently around a mild {{cvt|64|°F|1}}. This phenomenon, together with cool breezes from the Pacific Ocean, keeps Eureka relatively cool and mild, while contrasting with inland areas in relative proximity to Humboldt Bay, which are prone to extreme temperatures that often exceed {{cvt|100|°F|1}}. This causes frequent temperature differences between Eureka and [[Willow Creek, California#Climate|nearby inland areas]] during summer and early fall of {{cvt|30|to|40|F-change|C-change}}. Despite the common coastal fog, Eureka enjoys on average about 55% possible sunshine per year, about on par with cities such as [[Calgary]], [[Portland, Oregon|Portland]], [[New York City]] and [[Chicago]].<ref>{{cite web|url=ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/TABLES/REG_IV/US/GROUP2/00305801 |title=Table |website=ftp.atdd.noaa.gov |format=PDF |access-date=September 26, 2019}}</ref><ref>{{cite web|url=ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/TABLES/REG_IV/US/GROUP3/72530.TXT |title=Table |website=ftp.atdd.noaa.gov |format=PDF |access-date=September 26, 2019}}</ref><ref>{{cite web|url=ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/TABLES/REG_IV/US/GROUP4/72698.TXT |title=Table |website=ftp.atdd.noaa.gov |format=PDF |access-date=September 26, 2019}}</ref><ref>{{cite web | url=http://climate.weather.gc.ca/climate_normals/results_1981_2010_e.html?stnID=2205&lang=e&dCode=1&province=ALTA&provBut=Go&month1=0&month2=12 | title=Canadian Climate Normals 1981–2010 Station Data – Climate – Environment and Climate Change Canada| date=September 25, 2013}}</ref>

Annual precipitation averages {{cvt|40.3|in|mm|0}}. Measurable precipitation falls on an average of 127.5 days each year, concentrated heavily from October to April. On average, December is the wettest month, averaging over {{cvt|8|in|mm|1}} of precipitation, virtually all of it rain. The wettest "rain year" was from July 1889 to June 1890 with {{cvt|73.30|in|mm|1}} and the driest from July 1976 to June 1977 with {{cvt|17.56|in|mm|1}}. The greatest monthly precipitation was {{cvt|23.21|in|mm|1}} in December 2002. The greatest 24-hour precipitation was {{cvt|6.79|in|mm|1}} on December 27, 2002. However, historic 100-year dramatic weather events such as the [[Christmas Week flood of 1955]] and, especially, the [[Christmas flood of 1964]], which severely damaged the region, may not be reflected in records listed herein. Snowfall on the coast happens only on rare occasions, averaging {{cvt|0.2|in|cm}} as of the 1981–2010 normals, but only five years during that period received measurable snowfall.<ref name = NOAA/><!--1. Product: "First/last dates"; 2. Variable: "Snowfall >= 0.1 in"; 3. Year; 1981–2010; Probability = 17%--> The most snowfall in one month was {{cvt|6.9|in|cm}} in January 1907.

{{Weather box
|location = Eureka, California ([[National Weather Service|NWS]] Forecast Office, [[Woodley Island]]) (1991–2020 normals,{{efn|Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1991 to 2020.}} extremes 1886–present)
|single line = Y
|Jan record high F = 78
|Feb record high F = 85
|Mar record high F = 78
|Apr record high F = 80
|May record high F = 84
|Jun record high F = 85
|Jul record high F = 77
|Aug record high F = 82
|Sep record high F = 87
|Oct record high F = 87
|Nov record high F = 81
|Dec record high F = 77
| Jan avg record high F = 66.1
| Feb avg record high F = 66.5
| Mar avg record high F = 65.9
| Apr avg record high F = 67.6
| May avg record high F = 69.4
| Jun avg record high F = 69.0
| Jul avg record high F = 69.4
| Aug avg record high F = 71.7
| Sep avg record high F = 74.3
| Oct avg record high F = 74.8
| Nov avg record high F = 68.2
| Dec avg record high F = 64.8
|year avg record high F = 78.4
|Jan high F = 55.1
|Feb high F = 55.4
|Mar high F = 56.1
|Apr high F = 57.4
|May high F = 59.6
|Jun high F = 61.9
|Jul high F = 63.1
|Aug high F = 64.0
|Sep high F = 63.9
|Oct high F = 61.9
|Nov high F = 57.8
|Dec high F = 54.7
|year high F= 59.2
|Jan mean F = 47.9
|Feb mean F = 48.4
|Mar mean F = 49.2
|Apr mean F = 50.8
|May mean F = 53.7
|Jun mean F = 56.0
|Jul mean F = 57.7
|Aug mean F = 58.5
|Sep mean F = 57.2
|Oct mean F = 54.3
|Nov mean F = 50.5
|Dec mean F = 47.4
|year mean F= 52.6
|Jan low F = 40.8
|Feb low F = 41.3
|Mar low F = 42.4
|Apr low F = 44.2
|May low F = 47.7
|Jun low F = 50.1
|Jul low F = 52.4
|Aug low F = 53.0
|Sep low F = 50.5
|Oct low F = 46.8
|Nov low F = 43.2
|Dec low F = 40.0
|year low F= 46.0
| Jan avg record low F = 31.8
| Feb avg record low F = 32.7
| Mar avg record low F = 34.2
| Apr avg record low F = 36.6
| May avg record low F = 40.9
| Jun avg record low F = 44.4
| Jul avg record low F = 48.6
| Aug avg record low F = 48.8
| Sep avg record low F = 44.9
| Oct avg record low F = 38.7
| Nov avg record low F = 33.3
| Dec avg record low F = 30.7
|year avg record low F = 28.9
|Jan record low F = 20
|Feb record low F = 24
|Mar record low F = 29
|Apr record low F = 31
|May record low F = 35
|Jun record low F = 40
|Jul record low F = 43
|Aug record low F = 44
|Sep record low F = 36
|Oct record low F = 32
|Nov record low F = 27
|Dec record low F = 21
|precipitation colour = green
|Jan precipitation inch = 6.67
|Feb precipitation inch = 5.64
|Mar precipitation inch = 5.75
|Apr precipitation inch = 3.64
|May precipitation inch = 1.66
|Jun precipitation inch = 0.70
|Jul precipitation inch = 0.18
|Aug precipitation inch = 0.18
|Sep precipitation inch = 0.68
|Oct precipitation inch = 2.31
|Nov precipitation inch = 4.89
|Dec precipitation inch = 8.10
|year precipitation inch=40.40
|Jul snow inch = 0.0
|Aug snow inch = 0.0
|Sep snow inch = 0.0
|Oct snow inch = 0.0
|Nov snow inch = 0.0
|Dec snow inch = 0.0
|Jan snow inch = 0.0
|Feb snow inch = 0.0
|Mar snow inch = 0.0
|Apr snow inch = 0.0
|May snow inch = 0.0
|Jun snow inch = 0.0
|year snow inch= 0.0
|unit precipitation days = 0.01 in
|Jan precipitation days = 16.5
|Feb precipitation days = 15.4
|Mar precipitation days = 16.0
|Apr precipitation days = 13.8
|May precipitation days = 9.3
|Jun precipitation days = 5.5
|Jul precipitation days = 3.0
|Aug precipitation days = 3.5
|Sep precipitation days = 4.7
|Oct precipitation days = 8.7
|Nov precipitation days = 14.3
|Dec precipitation days = 17.1
|year precipitation days=
|unit snow days = 0.1 in
| Jul snow days = 0.0
| Aug snow days = 0.0
| Sep snow days = 0.0
| Oct snow days = 0.0
| Nov snow days = 0.0
| Dec snow days = 0.0
| Jan snow days = 0.1
| Feb snow days = 0.0
| Mar snow days = 0.0
| Apr snow days = 0.0
| May snow days = 0.0
| Jun snow days = 0.0
|year snow days = 0.1
|Jan sun = 140.1
|Feb sun = 143.7
|Mar sun = 207.4
|Apr sun = 253.1
|May sun = 280.5
|Jun sun = 277.7
|Jul sun = 273.4
|Aug sun = 236.5
|Sep sun = 220.3
|Oct sun = 175.8
|Nov sun = 131.3
|Dec sun = 126.2
|year sun = 2466.0
|Jan percentsun = 47
|Feb percentsun = 48
|Mar percentsun = 56
|Apr percentsun = 63
|May percentsun = 63
|Jun percentsun = 62
|Jul percentsun = 60
|Aug percentsun = 55
|Sep percentsun = 59
|Oct percentsun = 51
|Nov percentsun = 44
|Dec percentsun = 44
|year percentsun = 55
|source 1 = NOAA (sun 1961–1990)<ref name = NOAA>{{cite web
| url = http://w2.weather.gov/climate/xmacis.php?wfo=eka
| title = NowData – NOAA Online Weather Data
| publisher = [[National Oceanic and Atmospheric Administration]]
| access-date = September 23, 2013
| archive-date = September 21, 2016
| archive-url = https://web.archive.org/web/20160921061615/http://w2.weather.gov/climate/xmacis.php?wfo=eka
| url-status = dead
}}</ref><ref name=NOAAtxt>
{{cite web
| url = https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-monthly-1991-2020&stations=USW00024213&format=pdf&dataTypes=MLY-TMAX-NORMAL,MLY-TMIN-NORMAL,MLY-TAVG-NORMAL,MLY-PRCP-NORMAL,MLY-SNOW-NORMAL
| title = U.S. Climate Normals Quick Access &ndash; Station: Eureka WFO Woodley Island, CA
| publisher = [[National Oceanic and Atmospheric Administration]]
| access-date = February 23, 2023
| archive-url = https://web.archive.org/web/20230508013007/https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-monthly-1991-2020&stations=USW00024213&format=pdf&dataTypes=MLY-TMAX-NORMAL,MLY-TMIN-NORMAL,MLY-TAVG-NORMAL,MLY-PRCP-NORMAL,MLY-SNOW-NORMAL
| archive-date = May 8, 2023}}</ref><ref name=NOAAsun>
{{cite web
| url = ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/TABLES/REG_IV/US/GROUP3/72594.TXT
| title = WMO Climate Normals for Eureka/WSO City, CA 1961–1990
| publisher = [[National Oceanic and Atmospheric Administration]]
| access-date = September 23, 2015
| archive-url = https://web.archive.org/web/20230508012701/ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/TABLES/REG_IV/US/GROUP3/72594.TXT
| archive-date = May 8, 2023}}</ref>
}}
{{Graph:Weather monthly history
| table=Ncei.noaa.gov/weather/Eureka.tab
| title=Eureka monthly weather statistics
}}