You may be interested in this way of treating data. It has a Google Maps interface in one pane. You can choose a region, and it will show the stations with flags in Google Maps. Choosing more than one region is possible, but it gets slow. You can choose different sets (GHCN etc), and select by start and end dates.

But then if you click on a flag, it shows a plot of the annual temperature data on the left pane. It's an active plot, and you can stretch or shrink the axes.

Here is a simpler version that just displays stations (Google Maps), but lets you choose in various ways. It's like KML, but more flexible.