diff --git a/lib/pure/times.nim b/lib/pure/times.nim
index 68a457084..553e3fe01 100644
--- a/lib/pure/times.nim
+++ b/lib/pure/times.nim
@@ -77,6 +77,8 @@ when defined(posix) and not defined(JS):
 
   when not defined(freebsd) and not defined(netbsd) and not defined(openbsd):
     var timezone {.importc, header: "<time.h>".}: int
+    proc tzset(): void {.importc, header: "<time.h>".}
+    tzset()
 
 elif defined(windows):
   import winlean