hotter/colder is made with the Forecast.io and the Mapquest and Openstreetmap API, a lot of mistakes, a little bit of Twitter Bootstrap and the FitText plugin.
Who made hotter/colder? Me, Jacopo Colò (but the idea is Chiara Lino's). It's my first program of more than 50 lines: if something doesn't work, be patient. Or, even better, post a new issue on GitHub or write to me on Twitter.