@ivo said:

Windyty uses different weather data sources, mainly GFS forecast model, produced by NOAA and NEMS model produced by Swiss weather geniuses from Meteoblue.com. By hovering mouse over small info link, you will get info about currently used model, and update time.

Very nice project,
I wonder if have you the possibility to collect meteo data from PWS for best local results ??? (like weather underground)