How to install Ubuntu's world clock applet in Xubuntu

One of the visual improvements in this new version of Ubuntu is on the clock that sits on the Gnome panel. It now shows much more information. Apart from time and date, it now shows the weather conditions for your current location. It was disappointing to see that Xubuntu didn’t have it by default, so I have written a very easy and small guide on how to install it in Xubuntu.