diff --git a/lisp/calendar/time-date.el b/lisp/calendar/time-date.el
index 155c34927f..6407138953 100644
--- a/lisp/calendar/time-date.el
+++ b/lisp/calendar/time-date.el
@@ -153,19 +153,25 @@ date-to-time
   "Parse a string DATE that represents a date-time and return a time value.
 DATE should be in one of the forms recognized by `parse-time-string'.
 If DATE lacks timezone information, GMT is assumed."
-  (condition-case err
-      (encode-time (parse-time-string date))
-    (error
-     (let ((overflow-error '(error "Specified time is not representable")))
-       (if (equal err overflow-error)
-	   (signal (car err) (cdr err))
-	 (condition-case err
-	     (encode-time (parse-time-string
-			   (timezone-make-date-arpa-standard date)))
-	   (error
-	    (if (equal err overflow-error)
-		(signal (car err) (cdr err))
-	      (error "Invalid date: %s" date)))))))))
+  ;; Pass the result of parsing through decoded-time-set-defaults
+  ;; because encode-time signals if HH:MM:SS are not filled in.
+  (encode-time
+    (decoded-time-set-defaults
+      (condition-case err
+          (parse-time-string date)
+        (error
+         (let ((overflow-error '(error "Specified time is not representable")))
+           (if (or (equal err overflow-error)
+                   ;; timezone-make-date-arpa-standard misbehaves if
+                   ;; not given at least HH:MM as part of the date.
+                   (not (string-match ":" date)))
+               (signal (car err) (cdr err))
+             (condition-case err
+                 (parse-time-string (timezone-make-date-arpa-standard date))
+               (error
+                (if (equal err overflow-error)
+                    (signal (car err) (cdr err))
+                  (error "Invalid date: %s" date)))))))))))
 
 ;;;###autoload
 (defalias 'time-to-seconds 'float-time)