As usual, I compared the previously posted TempLS distribution to the GISS plot. Unusually, there was a significant discrepancy, which turned out to be a kind of Y2012 issue in my code.
Update - on further checking the error was simple - I had plotted Jan 2011.
Here is GISS:
It's broadly similar to the one I posted here, but it gets the USA and N Africa quite wrong. So I went back to check. I was aware of the date issue, because my plot was dated Jan 2011, as I noted. I thought that was the only effect, but I was wrong (in fact, the whole plot was Jan 2011). When I re-ran, ,aking sure my script now detected the year as well as the month, I got:
This now matches well. The white blob far NW is where the cold runs off the color scale. The date error did not affect the monthly average number, only the plot.
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