building a weather App

@IBOutlet weak var iconView: UIImageView!
@IBOutlet weak var currentTimeLabel: UILabel!
@IBOutlet weak var temperatureLabel: UILabel!
@IBOutlet weak var humidityLabel: UILabel!
@IBOutlet weak var precipitationLabel: UILabel!
@IBOutlet weak var summaryLabel: UILabel!
@IBOutlet weak var refreshButton: UIButton!
@IBOutlet weak var refreshActivityIndicator: UIActivityIndicatorView!

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

    getCurrentWeatherData()
}

func getCurrentWeatherData() -> Void {
    let baseURL = NSURL(string: "https://api.forecast.io/forecast/\(apiKey)/")
    let forecastURL = NSURL(string: "37.8267,-122.423", 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.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)"

                //Stop refresh animation
                self.refreshActivityIndicator.stopAnimating()
                self.refreshActivityIndicator.hidden = true
                self.refreshButton.hidden = true
            })

        }

    })

    downloadTask.resume()
}


@IBAction func refresh() {
    getCurrentWeatherData()

    refreshButton.hidden = true
    refreshActivityIndicator.hidden = false
    refreshActivityIndicator.startAnimating()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}