diff --git a/TM/plotting.py b/TM/plotting.py
index f6ae105185df631e5dc273f9d466aad0fded6787..ea5356d073c19fef38279bb3c512647fd26887f1 100644
--- a/TM/plotting.py
+++ b/TM/plotting.py
@@ -586,6 +586,10 @@ def plot_timeline(infile, threshold=None, numTemplates=0, colorBy='templateNumbe
         # Give some margin
         minMag = math.floor(minMag * 10) / 10 - 0.2
         maxMag = math.ceil(maxMag * 10) / 10 + 0.3
+    else:
+        minMag = 0.
+        maxMag = 0.
+
 
     # 2. For histogram
     # 2.1. Maximum rates