--- a/NEWS
+++ b/NEWS
@@ -65,6 +65,13 @@
     functions.  Packages that implement extra colormaps should use these
     commands with PKG_ADD and PKG_DEL statements.
 
+ ** The datevec function has been extended for better Matlab compatibility.
+    It now accepts string inputs in the following numerical formats: 12, 21,
+    22, 26, 29, 31.  This is undocumented, but verifiable, Matlab behavior.
+    In addition, the default for formats which do not specify a date is
+    January 1st of the current year.  The previous default was the current day,
+    month, and year.  This may produce changes in existing scripts.
+
  ** Other new functions added in 3.8.0:
 
       colorcube   splinefit

--- a/scripts/time/datevec.m
+++ b/scripts/time/datevec.m
@@ -29,7 +29,12 @@
 ## month, day, hour, minute, and seconds respectively.
 ##
 ## @var{f} is the format string used to interpret date strings
-## (see @code{datestr}).
+## (see @code{datestr}).  If @var{date} is a string, but no format is
+## specified, then a relatively slow search is performed through various
+## formats.  It is always preferable to specifiy the format string @var{f}
+## if it is known.  Formats which do not specify a particular time component
+## will have the value set to zero.  Formats which do not specify a date will
+## default to January 1st of the current year.
 ##
 ## @var{p} is the year at the start of the century to which two-digit years
 ## will be referenced.  If not specified, it defaults to the current year
@@ -53,7 +58,7 @@
   if (isempty (std_formats))
     std_formats = cell ();
     nfmt = 0;
-    ## These formats are specified by Matlab to be parsed
+    ## These formats are specified by Matlab documentation to be parsed
     ## The '# XX' refers to the datestr numerical format code
     std_formats{++nfmt} = "dd-mmm-yyyy HH:MM:SS";   # 0
     std_formats{++nfmt} = "dd-mmm-yyyy";            # 1
@@ -65,6 +70,14 @@
     std_formats{++nfmt} = "HH:MM PM";               # 16
     std_formats{++nfmt} = "mm/dd/yyyy";             # 23
 
+    ## These formats are undocumented but parsed by Matlab
+    std_formats{++nfmt} = "mmmyy";                  # 12
+    std_formats{++nfmt} = "mmm.dd,yyyy HH:MM:SS";   # 21
+    std_formats{++nfmt} = "mmm.dd,yyyy";            # 22
+    std_formats{++nfmt} = "yyyy/mm/dd";             # 26
+    std_formats{++nfmt} = "yyyy-mm-dd";             # 29
+    std_formats{++nfmt} = "yyyy-mm-dd HH:MM:SS";    # 31
+
     ## These are other formats that Octave tries
     std_formats{++nfmt} = "mmm-dd-yyyy HH:MM:SS";
     std_formats{++nfmt} = "mmm-dd-yyyy";
@@ -76,7 +89,6 @@
     std_formats{++nfmt} = "dd.mmm.yyyy";
     std_formats{++nfmt} = "mmm.dd.yyyy HH:MM:SS";
     std_formats{++nfmt} = "mmm.dd.yyyy";
-    std_formats{++nfmt} = "mmmyy";                  # 12
     std_formats{++nfmt} = "mm/dd/yyyy HH:MM";
   endif
 
@@ -254,9 +266,10 @@
     endif
     if (! fy && ! fm && ! fd)
       tmp = localtime (time ());
+      ## default is January 1st of current year
       y = tmp.year + 1900;
-      m = tmp.mon + 1;
-      d = tmp.mday;
+      m = 1;
+      d = 1;
     elseif (! fy && fm && fd)
       tmp = localtime (time ());
       y = tmp.year + 1900;
@@ -280,21 +293,21 @@
 %! ## Current date and time
 %! datevec (now ())
 
-%!shared nowvec
-%! nowvec = datevec (now); # Some tests could fail around midnight!
-%!# tests for standard formats: 0, 1, 2, 6, 13, 14, 15, 16, 23
+%!shared yr
+%! yr = datevec (now)(1);  # Some tests could fail around midnight!
+## tests for standard formats: 0, 1, 2, 6, 13, 14, 15, 16, 23
 %!assert (datevec ("07-Sep-2000 15:38:09"), [2000,9,7,15,38,9])
 %!assert (datevec ("07-Sep-2000"), [2000,9,7,0,0,0])
 %!assert (datevec ("09/07/00"), [2000,9,7,0,0,0])
-%!assert (datevec ("09/13"), [nowvec(1),9,13,0,0,0])
-%!assert (datevec ("15:38:09"), [nowvec(1:3),15,38,9])
-%!assert (datevec ("3:38:09 PM"), [nowvec(1:3),15,38,9])
-%!assert (datevec ("15:38"), [nowvec(1:3),15,38,0])
-%!assert (datevec ("03:38 PM"), [nowvec(1:3),15,38,0])
+%!assert (datevec ("09/13"), [yr,9,13,0,0,0])
+%!assert (datevec ("15:38:09"), [yr,1,1,15,38,9])
+%!assert (datevec ("3:38:09 PM"), [yr,1,1,15,38,9])
+%!assert (datevec ("15:38"), [yr,1,1,15,38,0])
+%!assert (datevec ("03:38 PM"), [yr,1,1,15,38,0])
 %!assert (datevec ("03/13/1962"), [1962,3,13,0,0,0])
 
 %% Test millisecond format FFF
-%!assert (datevec ("15:38:21.25", "HH:MM:SS.FFF"), [nowvec(1:3),15,38,21.025])
+%!assert (datevec ("15:38:21.25", "HH:MM:SS.FFF"), [yr,1,1,15,38,21.025])
 
 # Other tests
 %!assert (datenum (datevec ([-1e4:1e4])), [-1e4:1e4]');