InterfaceController.m

- (IBAction)updateAction {
    NSURLRequest* requestForWeatherData = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://api.openweathermap.org/data/2.5/weather?q=London,UK&APPID=????????????"]];
    //NOTE : ???? is here -> openweathermap api key write
    NSURLSession *session = [NSURLSession sharedSession];
   
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:requestForWeatherData completionHandler:^(NSData * data, NSURLResponse * response, NSError * error) {
        
        NSMutableDictionary *allData = [ NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];
        NSLog(@"%@ - Error %@", allData,error);
        //data in serialized view
        NSString* currentWeather = nil;
        
        NSArray* weather = allData[@"weather"];
        for (NSDictionary* weatherDictionary in weather) {
            currentWeather = weatherDictionary[@"main"];
        }
        
        [self setImageAndTextWithWeather:currentWeather];
        
    }];
    
    [dataTask resume];

}