JSON Data for weather is nil when I run the app, but on the web page

thank you for answering.

This has been annoying me for days now and I've tried everything I can to fix it. For some reason the data parameter in this chunk of code:

    let task = NSURLSession.sharedSession().dataTaskWithURL(url, completionHandler: {
        (data, response, error) in
        dispatch_async(dispatch_get_main_queue(), {
            do {
                let json = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as! NSDictionary

                if let main = json["main"] as? NSDictionary {
                    if let temp = main["temp"] as? Double {
                        self.temperature = String(format: "%.1f", temp);
                        print(self.temperature);
                    }
                }
            } catch (let error as NSError) {
                print(error);
            }
        });
    });

is ALWAYS nil. I've made sure the url is correct by copying and pasting it into safari, and when I go on the website, the data is on the page. Is there anything I have to fix?

Btw, here's the code that calls this part:

if (coordinate != nil) {
        info.getWeatherData("http://ift.tt/2atUfGV, its a secret}");
        print("api