English: Bar chart of global surface temperature, with bars color-coded by El Niño and La Niña intensity.

Chart shows correlation of the (regional) El Niño–Southern Oscillation to global mean surface temperature. Suggested caption:

Colored bars show how El Niño years (red, regional warming) and La Niña years (blue, regional cooling) relate to overall global warming. El Niño years usually correspond to average global temperature increases, and La Niña years usually contribute to average global temperature decreases.

El Niño and La Niña intensity data is based on a year extending, roughly, from July of one year to June of the following year. Accordingly, I formed 12-month averages of global mean surface temperature anomalies from HadCRUT data extending from July to June, rather than the conventional calendar-year averaging.

The height of each bar is determined by temperature change for that time period, and the color of the bar is determined by the El Niño and La Niña intensity category in that time period.

The dark background, and black outlines of the individual bars, enable the colors to be seen more vividly.

Circles were added to blue bars to help color-blind readers.

• El Niño and La Niña intensity data: https://ggweather.com/enso/oni.htm

— 14 Aug 2021 archive thereof: https://web.archive.org/web/20210814091839/https://ggweather.com/enso/oni.htm

— 17 Jan 2023 archive thereof: https://web.archive.org/web/20230117015049/https://ggweather.com/enso/oni.htm

— 21 July 2023 archive thereof: https://web.archive.org/web/20230721183926/https://ggweather.com/enso/oni.htm

Source explains: The Oceanic Niño Index (ONI) has become the de-facto standard that NOAA uses for identifying El Niño (warm) and La Niña (cool) events in the tropical Pacific. It is the running 3-month mean SST anomaly for the Niño 3.4 region (i.e., 5oN-5oS, 120o-170oW). Events are defined as 5 consecutive overlapping 3-month periods at or above the +0.5o anomaly for warm (El Niño) events and at or below the -0.5 anomaly for cold (La Niña) events. The threshold is further broken down into Weak (with a 0.5 to 0.9 SST anomaly), Moderate (1.0 to 1.4), Strong (1.5 to 1.9) and Very Strong (≥ 2.0) events. For the purpose of this report for an event to be categorized as weak, moderate, strong or very strong it must have equaled or exceeded the threshold for at least 3 consecutive overlapping 3-month periods.

• Source for temperature data after Met Office upgraded to HadCRUT5 data, used for January 2023 version of this chart:

— https://www.metoffice.gov.uk/hadobs/hadcrut5/data/current/download.html (choose HadCRUT.5.0.1.0 analysis, Summary series, Global (NH+SH)/2, monthly to use Download link) and average July through June data as described above.

— 30 January 2023 archive thereof: https://web.archive.org/web/20230130195642/https://www.metoffice.gov.uk/hadobs/hadcrut5/data/current/download.html

— 23 July 2023 archive thereof: https://web.archive.org/web/20230723052905/https://www.metoffice.gov.uk/hadobs/hadcrut5/data/current/download.html

— Version 8 (23 July 2023): Temperatures from HadCRUT were adjusted by 0.3566 °C so that this chart shows temperature changes (vertical axis) since the pre-industrial period 1850-1900.

For earlier versions:

• Source for temperature data when old HadCRUT4 data was used in earlier versions of this chart: https://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.4.6.0.0.monthly_ns_avg.txt

— 21 March 2021 archive thereof: https://web.archive.org/web/20210321090452/https://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.4.6.0.0.monthly_ns_avg.txt

• MetOffice's description of data file format: https://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/series_format.html

— 13 March 2021 archive thereof: https://web.archive.org/web/20210313052050/https://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/series_format.html

Technical note: Most of the XML text for this SVG file was automatically generated by an adaptation of the Warming stripes bar chart spreadsheet linked at User:RCraig09/Excel to XML for SVG.

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