Because Frank E. L. asked me about related issues, I have downloaded all the monthly/regional Czech Hydrometeorological Institute's temperature data from the years 1961-2012 to Mathematica and calculated all statistical quantities I considered interesting.
First, I had to figure out the right URLs of the HTML pages that contain the tables in an importable enough format, import them with some sensible formatting options to Mathematica so that they quickly become an array, and replace decimal commas by decimal points.
When we're done, we have the temperature for each of the 12 months of each of the 52 years for each of the 1+13 regions of the Czech Republic. Just to be sure, Czechia has 14 administrative regions (the division was different in the era of communism and it's not one of the things in which I considered communism to be worse: I don't really care) but in this dataset, Prague is unified with the Central Bohemian region that surrounds the capital which means that we only have 13 "weather regions" but they're sometimes supplemented by the new 14th region (put at the beginning) which is the whole country.
Well, your humble correspondent rewrote the names of the regions with the right character set and diacritics. It still displayed incorrectly in the PDF and most readers can't read Czech, anyway. ;-)