diff --git a/elastalert/ruletypes.py b/elastalert/ruletypes.py
index 47509f62..aa64a246 100644
--- a/elastalert/ruletypes.py
+++ b/elastalert/ruletypes.py
@@ -522,12 +522,15 @@ def add_match(self, match, qk):
 
     def find_matches(self, ref, cur):
         """ Determines if an event spike or dip happening. """
+        if ref is None or cur is None:
+            return False
+
         # Apply threshold limits
         if self.field_value is None:
             if (cur < self.rules.get('threshold_cur', 0) or
                     ref < self.rules.get('threshold_ref', 0)):
                 return False
-        elif ref is None or ref == 0 or cur is None or cur == 0:
+        elif ref == 0 or cur == 0:
             return False
 
         spike_up, spike_down = False, False