Somthing is wrong with the interaction with the ui to the code

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    let baseUrl = NSURL(string:"https://api.forecast.io/forecast/\(apiKey)/")

    let forecastURL = NSURL(string:"28.014087,-82.787620", relativeToURL: baseUrl)

    let sharedSession = NSURLSession.sharedSession()
    let downloadTask: NSURLSessionDownloadTask = sharedSession.downloadTaskWithURL(forecastURL!, completionHandler:{(location:NSURL!,response:NSURLResponse!,error:NSError!) -> Void in
        if (error == nil){
        let dataObject = NSData(contentsOfURL: location)
        let weatherDictionary: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataObject!, options: nil, error: nil) as NSDictionary


            let currentWeather = Current(weatherDictionary:weatherDictionary)

            dispatch_async(dispatch_get_main_queue(), { () -> Void in
                self.temperatureLabel.text = "\(currentWeather.temperature)"
                self.temperatureLabel.text = "\(currentWeather.temperature)"
                self.iconView.image = currentWeather.icon!
                self.currentTimeLabel.text = "At \(currentWeather.currentTime!) it is"
                self.humidityLabel.text = "\(currentWeather.humidity)"
                self.precipitationLabel.text = "\(currentWeather.precipProbability)"
                self.summaryLabel.text = "\(currentWeather.summary)"
            })

        }

    })
    downloadTask.resume()