diff --git a/NDVITrend.py b/NDVITrend.py
index 79b871f715e614fec172b9c5395433479c2e3df2..0449678471499edcafb0e2f450d6aa959e319585 100644
--- a/NDVITrend.py
+++ b/NDVITrend.py
@@ -19,7 +19,7 @@ def getDatesFromFiles(fld,
             dt = os.path.basename(f)[date_pos:date_pos + date_len]
             if date_jul:
                 y, jd = int(dt[0:4]), int(dt[4:7])
-                dt = (datetime.datetime(y, 1, 1) + datetime.timedelta(jd)).strftime('%Y%m%d')
+                dt = (datetime.datetime(y, 1, 1) + datetime.timedelta(jd - 1)).strftime('%Y%m%d')
             df.write(dt + '\n')
 
     return
@@ -45,7 +45,7 @@ def temporalSmoothing(fld,
             dt = os.path.basename(f)[date_pos:date_pos+date_len]
             if date_jul:
                 y,jd = int(dt[0:4]),int(dt[4:7])
-                dt = (datetime.datetime(y,1,1) + datetime.timedelta(jd)).strftime('%Y%m%d')
+                dt = (datetime.datetime(y,1,1) + datetime.timedelta(jd - 1)).strftime('%Y%m%d')
             df.write(dt+'\n')
             cmd += [f]