Update: I see that the plot does not show in Internet Explorer - I'm trying to find out why. It works in Firefox, Chrome and Safari.
In the previous post, I talked about a KMZ file which would display the stations of the four temperature databases, BEST, GHCN, GSOD and CRUTEM3. They were set in folders so that different starrting dates could be displayed.
Here you see just a single image. There are two legends, one with decade and one with database. You can click on the legend to bring up any combination. There is a control with a square and four triangles. The triangles just navigate up and down the menus in the way they point. The square enables you to toggle rapidly between the last two images shown. The intent is that you can set up pairings and compare.
The images are quite high resolution (1600x960 pixels) so you can use the Ctrl+ and Ctrl- controls to enlarge and see more detail. When you click on an image for the first time, there is a short pause while it downloads.
As you'll see, the daily data, GSOD, has good coverage at present, but doesn't go back far. GHCN goes a long way back, and the BEST coverage seems to use much the same data, with just a few more ststions. But try it out - there is a lot you can test.