diff --git a/geomagio/algorithm/AverageAlgorithm.py b/geomagio/algorithm/AverageAlgorithm.py
index dd939264be16cd8b5d6bc37b8077cca2dc79d699..ace31bcab4525ac78ccca587e3f39fbf4624b81e 100644
--- a/geomagio/algorithm/AverageAlgorithm.py
+++ b/geomagio/algorithm/AverageAlgorithm.py
@@ -65,7 +65,7 @@ class AverageAlgorithm(Algorithm):
             if first:
                 self._stats = ts.stats
                 self._npts = ts.stats.npts
-                selt._stt = ts.stats.starttime
+                self._stt = ts.stats.starttime
                 first = False
 
             if ts.stats.npts != self._npts: