如何从openinnmap的位置获取天气

Question

我正在尝试从该位置获取天气。位置正确获取但未获得天气信息。请帮我解决此问题

getWeatherData("api.openweathermap.org/data/2.5/weather?q=\(city)")
func getWeatherData (urlString:String)
{
    let url = NSURL(string: urlString)
    let task = NSURLSession.sharedSession().dataTaskWithURL(url!) {(data,response,error) in
        dispatch_async(dispatch_get_main_queue()) {
            self.setWeatherData(data!)
        }
    }
}
func setWeatherData(weatherData:NSData)
{
    let json = try! NSJSONSerialization.JSONObjectWithData(weatherData, options: []) as! NSDictionary

    if let main = json["main"] as? NSDictionary{
        if let temp = main["temp"] as? Double{
            weather = String(format: "%.1f", temp)
        }
    }
}