General notes:

• Credit for general concept of w:warming stripes: climate scientist Ed Hawkins, w:University of Reading, U.K.
• Data values are visualized using color rather than locations of points on a graph.
• The average temperature in reference period 1951-1980 determines boundary between blue and red.
• Horizontal scale is time, from 1850 (left) to 2018 (right).
• Each hue (up to 8 blue and 8 red) covers a temperature range of 0.1 degrees Celsius.
• Data is global (not for a locality).

Source documentation re the underlying data:

• http://berkeleyearth.lbl.gov/auto/Global/Land_and_Ocean_summary.txt

• Archive (data through 2018): https://web.archive.org/web/20190512213725/http://berkeleyearth.lbl.gov/auto/Global/Land_and_Ocean_summary.txt
• More recent archive (data through 2020): https://web.archive.org/web/20211208161213/http://berkeleyearth.lbl.gov/auto/Global/Land_and_Ocean_summary.txt

"This file contains a brief summary of the changes in Earth's global average surface temperature estimated by combining the Berkeley Earth land-surface temperature field with a reinterpolated version of the HadSST ocean temperature a field. Two versions of this average are reported. These differ in how they treat locations with sea ice. In the first version, temperature anomalies in the presence of sea ice are extrapolated from land-surface air temperature anomalies. In the second version, temperature anomalies in the presence of sea ice are extrapolated from sea-surface water temperature anomalies (usually collected from open water areas on the periphery of the sea ice). ...

"Temperatures are in Celsius and reported as anomalies relative to the Jan 1951-Dec 1980 average. ...

"The land component is based on 45756 time series with 18875309 monthly data points

"The ocean component is based on 376898952 instantaneous water temperature observations"

Other datasets at Berkeley Earth:

• http://berkeleyearth.org/data/
• https://web.archive.org/web/20190629180117/http://berkeleyearth.org/data/

I found the dataset for this graphic by clicking through "annual summary"

Land + Ocean (1850 – Recent) ...

Monthly Global Average Temperature (annual summary)

Creator/Uploader's remarks:

• This warming stripe graphic is based on the year-wise average of the two datasets described above (namely, when sea ice is present, measuring air temp above the ice and measuring water temp below the ice).
• I averaged the datasets year by year in Microsoft Excel, and separated the averaged values into categories with "cutoff" (boundary) temperatures being multiples of 0.1 degrees Celsius (a simple linear relation). I assembled color-coded rectangles in Microsoft Powerpoint, exported, and re-sized using Photoshop.
• My resulting warming stripes diagram differs from a well-publicized one (June 2019) published by Ed Hawkins because he may have used a different Berkeley Earth dataset than I did. Mine here is based on deviation from a 1951-1980 reference period average, whereas Hawkins' data used a 1971-2000 reference period (the mean value separates blue from red). My "cutoff" temperatures (which determine boundaries between adjacent color bands) may be different. I used a different color scheme.