diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index 761feab7..ae3f7345 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -1848,7 +1848,7 @@ def get_startdate_time_zone(r,row,startdatetime=None):
 
     partofday = getpartofday(row,r)
 
-    if startdatetime.tzinfo is None:
+    if startdatetime.tzinfo is None or str(startdatetime.tzinfo) in ['tzutc()','Ect/GMT']:
         timezone_str = 'UTC'
         try:
             startdatetime = timezone.make_aware(startdatetime)
@@ -1860,15 +1860,18 @@ def get_startdate_time_zone(r,row,startdatetime=None):
             lonavg = row.df[' longitude'].mean()
 
             tf = TimezoneFinder()
-            try:
-                timezone_str = tf.timezone_at(lng=lonavg, lat=latavg)
-            except (ValueError,OverflowError): # pragma: no cover
-                timezone_str = 'UTC'
-            if timezone_str is None: # pragma: no cover
-                timezone_str = tf.closest_timezone_at(lng=lonavg,
+            if row.df[' latitude'].std() != 0:
+                try:
+                    timezone_str = tf.timezone_at(lng=lonavg, lat=latavg)
+                except (ValueError,OverflowError): # pragma: no cover
+                    timezone_str = 'UTC'
+                if timezone_str is None: # pragma: no cover
+                    timezone_str = tf.closest_timezone_at(lng=lonavg,
                                                     lat=latavg)
                 if timezone_str is None: # pragma: no cover
                     timezone_str = r.defaulttimezone
+            else:
+                timezone_str = r.defaulttimezone
             try:
                 startdatetime = pytz.timezone(timezone_str).localize(
                     row.rowdatetime
@@ -1878,6 +1881,7 @@ def get_startdate_time_zone(r,row,startdatetime=None):
                     pytz.timezone(timezone_str)
                     )
         except KeyError: # pragma: no cover
+            print('mies')
             timezone_str = r.defaulttimezone
     else:
         timezone_str = str(startdatetime.tzinfo)
@@ -1886,7 +1890,6 @@ def get_startdate_time_zone(r,row,startdatetime=None):
     starttime = startdatetime.strftime('%H:%M:%S')
 
 
-
     return startdatetime,startdate,starttime,timezone_str,partofday