Forecast data is in imperial units although -c switch is used.

Created by: jottr

Example:

$ forecast -c -f


----------------------------------------------------------------------

                            Berlin, Germany                           

                   Partly Cloudy :: 64.2 F (17.9 C)                   

              Sun          Mon          Tue          Wed              
            18 / 10      19 / 10      18 / 11      21 / 14            

----------------------------------------------------------------------

SUNDAY
Sun and clouds mixed. High 64F. Winds ESE at 5 to 10 mph.

[...]

Weather Undergrounds api has a field fcttext_metric which returns the forecast data in the metric system. See the relevant documentation on txt_forecast.