GetWeather.cs

public async static Task<string> GetWeather(string City)
        {
            HttpClient client = new HttpClient();
        
            const string openweathermap_id = "xxxxxxxxxxxxxxxxxxxxxxxxxxxx";
            dynamic JSON = client.GetStringAsync("http://api.openweathermap.org/data/2.5/weather?q=" + City.ToLower() + "&APPID=" + openweathermap_id + "&units=metric").Result;

            // Be sure, there is no error.
            try
            {
                decimal temperature = JSON["main"]["temp"];
                string city = JSON["name"];

                return "In " + city + " hat es momentan " + temperature.ToString("0.00") + "°C, die Luftfeuchtigkeit beträgt " + JSON["main"]["humidity"] + "%";
            }
            catch (Exception ex)
            {
                try
                {
                    return JSON["cod"];
                }
                catch
                {
                    return ex.InnerException.Message;
                }
            }

        }