Very cool implementation and pre-loading action...it's almost impossible to talk about global temperatures without talking about climate change. A view that I think many people would find interesting is the map colored by temperature deltas, over a given time...i.e. let the user set start and beginning and color the map based on the difference (and yes, that will probably increase hits on your DB, so I'm guessing it may not be trivial to implement)
It's something that we wanted to show too. Apart from the technical complexity involved it would be hard to show warming. In the last century overall warming was maybe 1 deg C, but temperatures fluctuate from year to year by up to 15 degrees. Here is a delta graph for 1900 - 2012, for example:
https://www.evernote.com/shard/s5/sh/6d1d932a-c1ed-411d-9b74...
One way of doing it though would be to use a rolling average of, say, 5 years.
