diff --git a/lisp/version.el b/lisp/version.el
index a14d84eedd6..4da940292c2 100644
--- a/lisp/version.el
+++ b/lisp/version.el
@@ -59,7 +59,7 @@ to the system configuration; look at `system-configuration' instead."
 		 (cond ((featurep 'motif) ", Motif")
 		       ((featurep 'x-toolkit) ", X toolkit")
 		       (t ""))
-		 (format-time-string "%a %b %e %Y" emacs-build-time)
+		 (format-time-string "%a %Y-%m-%d" emacs-build-time)
                  emacs-build-system)))
     (if here 
         (insert version-string)