I’ve been putting some development work into what is a fairly complicated application that generates temperature anomalies across the world (fig 1). As you will realise, as well as requiring the latest observational data to calculate a mean temperature, you must also must have the average temperature for the same period to calculate an anomaly, which for periods that are not exactly monthly isn’t possible without daily mean temperatures for thousands of stations around the world which you won’t get without spending a great deal of money with the Met Office.
The cheapest solution is to take the monthly averages which they don’t seem to mind giving away. You then can, with a clever bit of curve fitting, come up with some polynomials to estimate a daily temperature. Once you have loaded your application with the historic data that’s freely available for the UK from the Met Office website, and added in the CRUTEM4 station data for the rest of the globe, you can generate an anomaly chart for the first 10 days of April as you can see (fig 2). There are a few obvious bad anomalies in the mix that I’ve plotted, but on the whole it’s workable, and can’t be too far from reality. It needs more work, and hopefully I can add 1981-2010 averages from the weather buoys and fixed rigs to help fill in a few of the gaps.
The output from the application illustrates extremely well just how warm the weather of the last week has been across Germany and eastern Europe, and how cold it’s been further north over Scotland and Scandinavia. I’ve still yet to verify my estimates just to see how close I am to reality. Here’s a bit more of a close up of the British Isles (fig 3).