diff --git a/System/Time.hsc b/System/Time.hsc
index b4a623e605398ead8d0df5067aaf9c2ac49cfeab..74293eeeb60a5b68315ae1a4fae9b4b8c85d64a1 100644
--- a/System/Time.hsc
+++ b/System/Time.hsc
@@ -104,7 +104,7 @@ module System.Time
 
 #ifdef __NHC__
 #include <time.h>
-#  ifdef __sun
+#  if defined(__sun) || defined(__CYGWIN32__)
 #    define HAVE_TZNAME 1
 #  else
 #    define HAVE_TM_ZONE 1