Editing Pacific Ocean (section)

== Climate ==
[[File:El nino north american weather.png|thumb|upright=1.1|Impact of [[El Niño]] and [[La Niña]] on North America]]
[[File:Tip 1979-10-12 0533Z.png|thumb|upright=1.1|[[Typhoon Tip]] at global peak intensity on 12 October 1979]]
The climate patterns of the Northern and Southern Hemispheres generally mirror each other. The [[trade winds]] in the southern and eastern Pacific are remarkably steady while conditions in the North Pacific are far more varied with, for example, cold winter temperatures on the east coast of Russia contrasting with the milder weather off [[British Columbia]] during the winter months due to the preferred flow of [[ocean current]]s.<ref>[https://www.britannica.com/EBchecked/topic/437703/Pacific-Ocean/36083/Islands#toc36085 "Pacific Ocean: Islands"], ''Encyclopædia Britannica''. Retrieved 13 June 2013.</ref>

In the tropical and subtropical Pacific, the [[El Niño Southern Oscillation]] (ENSO) affects weather conditions. To determine the phase of ENSO, the most recent three-month [[sea surface temperature]] average for the area approximately {{convert|3000|km|mi|abbr=on}} to the southeast of [[Hawaii]] is computed, and if the region is more than {{convert|0.5|C-change|1}} above or below normal for that period, then an [[El Niño]] or [[La Niña]] is considered in progress.<ref>{{cite web|url=http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf|title=ENSO: Recent Evolution, Current Status and Predictions|pages=5, 19–20|author=Climate Prediction Center |author-link=Climate Prediction Center|publisher=[[National Oceanic and Atmospheric Administration]]|date=30 June 2014|access-date=30 June 2014}}</ref>

In the tropical western Pacific, the [[monsoon]] and the related [[wet season]] during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass.<ref>Glossary of Meteorology (2009). [http://amsglossary.allenpress.com/glossary/search?p=1&query=monsoon&submit=Search Monsoon.] {{webarchive|url=https://web.archive.org/web/20080322122025/http://amsglossary.allenpress.com/glossary/search?p=1&query=monsoon&submit=Search |date=22 March 2008 }} American Meteorological Society. Retrieved on 16 January 2009.</ref> Worldwide, [[tropical cyclone]] activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures is the greatest; however, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active month. November is the only month in which all the [[tropical cyclone basins]] are active.<ref name="AOML FAQ G1">{{cite web|title=Frequently Asked Questions: When is hurricane season?|publisher=[[National Oceanic and Atmospheric Administration]]|access-date=25 July 2006|url=http://www.aoml.noaa.gov/hrd/tcfaq/G1.html|author1 = Atlantic Oceanographic and Meteorological Laboratory – Hurricane Research Division|author-link1=Atlantic Oceanographic and Meteorological Laboratory}}</ref> The Pacific hosts the two most active [[tropical cyclone basins]], which are the northwestern Pacific and the eastern Pacific. [[Pacific hurricane]]s form south of Mexico, sometimes striking the western Mexican coast and occasionally the Southwestern United States between June and October, while [[typhoon]]s forming in the northwestern Pacific moving into southeast and east Asia from May to December. Tropical cyclones also form in the [[South Pacific tropical cyclone|South Pacific basin]], where they occasionally impact island nations.<ref>{{Citation |last1=Chand |first1=Savin S. |title=A Review of South Pacific Tropical Cyclones: Impacts of Natural Climate Variability and Climate Change |date=2020 |url=https://doi.org/10.1007/978-3-030-32878-8_6 |work=Climate Change and Impacts in the Pacific |pages=251–273 |editor-last=Kumar |editor-first=Lalit |access-date=25 October 2023 |series=Springer Climate |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-32878-8_6 |isbn=978-3-030-32878-8 |last2=Dowdy |first2=Andrew |last3=Bell |first3=Samuel |last4=Tory |first4=Kevin|s2cid=212780026 }}</ref>

In the arctic, icing from October to May can present a hazard for shipping while persistent fog occurs from June to December.<ref>[https://www.cia.gov/the-world-factbook/oceans/pacific-ocean/ "Pacific Ocean"], ''World Factbook'', CIA. Retrieved 13 June 2013.</ref> A climatological low in the Gulf of Alaska keeps the southern coast wet and mild during the winter months. The [[Westerlies]] and associated [[jet stream]] within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between the tropics and Antarctica,<ref name="Stimac">John P. Stimac. [http://www.ux1.eiu.edu/~cfjps/1400/pressure_wind.html Air pressure and wind.] Retrieved on 8 May 2008.</ref> which records the coldest temperature readings on the planet. In the Southern hemisphere, because of the stormy and cloudy conditions associated with [[extratropical cyclone]]s riding the jet stream, it is usual to refer to the Westerlies as the Roaring Forties, Furious Fifties and Shrieking Sixties according to the varying degrees of latitude.<ref>{{cite book|last=Walker|first=Stuart|title=The sailor's wind |publisher=W.W. Norton & Company|date=1998|page=[https://archive.org/details/sailorswind00walk/page/91 91]|isbn=978-0-393-04555-0|url=https://archive.org/details/sailorswind00walk|url-access=registration}}</ref>