WeatherService/SignalR/Startup.cs

using Microsoft.AspNet.SignalR;
using Microsoft.Owin.Cors;
using Owin;

namespace WeatherService.SignalR
{
    class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            app.Map("/signalr", map =>
            {
                map.UseCors(CorsOptions.AllowAll);

                var hubConfiguration = new HubConfiguration();
                map.RunSignalR(hubConfiguration);
            });
        }
    }
}