Displaying Image but icon weahter didn't change at all!!! why? "Displaying Image"

func toImage() -> UIImage? {
        var imageName: String

        switch self{
        case .ClearDay:
            imageName = "clear-day"
        case .ClearNight:
            imageName = "clear-night"
        case .Rain:
            imageName = "rain"
        case .Snow:
            imageName = "snow"
        case .Sleet:
            imageName = "sleet"
        case .Wind:
            imageName = "wind"
        case .Fog:
            imageName = "fog"
        case .Cloudy:
            imageName = "cloudy"
        case .PartlyCloudyDay:
            imageName = "cloudy-day"
        case .PartlyCloudyNight:
            imageName = "cloudy-night"
        }

    return UIImage(named: imageName)
    }

let tempature: Int?
let humidity: Int?
let precipProbability: Int?
let summary: String?
var icon: UIImage? = UIImage(named: "default")




init(weatherDictionary: [String: AnyObject]) {
    tempature = weatherDictionary["temperature"] as? Int
    if let humidityFloat = weatherDictionary["humidity"] as? Double {
        humidity = Int(humidityFloat * 100)
    } else {
        humidity = nil
    }
    if let precipFloat = weatherDictionary["precipProbability"] as? Double {
        precipProbability = Int(precipFloat * 100)
    } else {
        precipProbability = nil
    }
    summary = weatherDictionary["summary"] as? String


    if let iconString = weatherDictionary["icon"] as? String,
        let weatherIcon: Icon = Icon(rawValue: iconString){
            icon = weatherIcon.toImage()
    }

}

help please...