Remove Object From Array Using Enumeration - ios

Question

I have an array of dictionaries. Each dictionary contains latitude and longitude so I'm getting the distance of each item from the current user location. If the distance in miles is greater than 20, that particular dictionary should be removed from the array. If the dictionary is not removed from the array, an annotation is created and added to an annotation array which is then used to add annotations to a map once the enumeration is finished. I'm only getting one annotation added when I should be getting three so I know I'm doing something wrong in my enumeration.
func checkDistanceAndAddPins() {
for gym in gyms {
var index = 0
let gymLatitude = gym["latitude"]!!.doubleValue
let gymLongitude = gym["longitude"]!!.doubleValue
let gymLocation = CLLocation(latitude: gymLatitude, longitude: gymLongitude)
let distance = gymLocation.distanceFromLocation(myLocation!)
let distanceInMeters = NSNumber(double: distance)
let metersDouble = distanceInMeters.doubleValue
let miles = metersDouble * 0.00062137
if miles > maxDistance {
gyms.removeAtIndex(index)
} else {
let location = CLLocationCoordinate2D(latitude: gymLatitude, longitude: gymLongitude)
gymAnnotation.title = gym["Name"] as? String
gymAnnotation.subtitle = gym["Address"] as? String
gymAnnotation.coordinate = location
gymAnnotation.gymPhoneNumber = gym["Phone"] as? String
if let website = gym["Website"] as? String {
gymAnnotation.gymWebsite = website
}
gymLocations.append(gymAnnotation)
}
index += 1
}
dispatch_async(dispatch_get_main_queue()) {
self.gymMap.addAnnotations(self.gymLocations)
}
}