--- locale-posix.scm.~1~	Mon Sep  7 19:41:41 2009
+++ locale-posix.scm	Sun Sep 13 07:58:41 2009
@@ -149,7 +149,7 @@
                       (let* ((o-m (next-match offset-re))
                              (off (if o-m (hms->offset (cadr o-m) (cddr o-m))
                                       ;XXX What does "ahead" mean?
-                                      (+ (timezone-component-ref tz 'std-offset) SEC/HR) ) ) )
+                                      (- (timezone-component-ref tz 'std-offset) SEC/HR) ) ) )
                         (set-timezone-component! tz 'dst-name (cadr n-m))
                         (set-timezone-component! tz 'dst-offset off)
                         ; Rule, if present, must be complete