I have the ARRSE toolbar on my Firefox browser and it shows the temperature in my part of the country. However, when I click on it, it shows the weather and temperatures for three days, but also gives the intriguing information about the "felt" temperature. Sometimes it says "5 degrees (Centigrade) on the toolbar, but "Feels like 3 degrees" on the expanded forecast. I can't for the life of me explain how they can sense a two-degree difference because I know I can't. Anybody any idea how they arrive at the "felt temperature" figures? Is it just a guess or is there some computer program involved?