Notice: Undefined variable: convert_to in google_weather_show()

Hello,

The convert_to in google_weather_show() function throws php notices when $convert_to variable is not defined.
I fixed this minor issue by adding an else line to the if statement at line 144:
if ($handler->forecast_information->unit_system->attributes()->data != variable_get('google_weather_units', 'SI')) {
$convert_to = variable_get('google_weather_units', 'SI');
}
else $convert_to = NULL;

Thanks...