Celsius to Fahrenheit UISwitch

       let coordinate: (lat: Double, long: Double) = (37.8267,-122.423) // Tuple


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

        }


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

func retrieveWeatherForecast() {
    let forecastService = ForecastService(APIKey: forecastAPIKey)
    forecastService.getForecast(coordinate.lat, long: coordinate.long) {
        (let currently) in

        if let currentWeather = currently {
            // Update UI
            dispatch_async(dispatch_get_main_queue() ) {// Specify main queue in parameter
                //Execute code. part of GCD (dispatch...) To make run on main thread. dispatch function used to make changes in the UI from background queue.

                if let temperature = currentWeather.temperature {

                    let celsius = (temperature - 32) * 5 / 9

                    if self.celciusToFahrenheit.on {

                        self.currentTemperatureLabel?.text = "\(celsius)º"

                    } else {

                        self.currentTemperatureLabel?.text = "\(temperature)º"
                    }
                }


                }



                if let humidity = currentWeather.humidity {
                    self.currentHumidityLabel?.text = "\(humidity)%"
                }
                if let precipitation = currentWeather.precipProbability {
                    self.currentPrecipitationLabel?.text = "\(precipitation)%"
                }

                if let icon = currentWeather.icon {
                    self.currentWeatherIcon?.image = icon
                }

                if let summary = currentWeather.summary {
                    self.currentWeatherSummary?.text = summary
                }
                self.toggleRefreshAnimation(false) //stopping toggle
            }

        }
    }
}

@IBAction func refreshWeather() {
    toggleRefreshAnimation(true) //starting toggle
    retrieveWeatherForecast() // To refresh put original online call in a func
}

func toggleRefreshAnimation(on: Bool) {

    refreshButton?.hidden = on
    if on {
        activityIndicator?.startAnimating()

    } else {
        activityIndicator?.stopAnimating()
    }

}