diff --git a/compton.c b/compton.c
index 92378b047..23e86dd32 100644
--- a/compton.c
+++ b/compton.c
@@ -5390,16 +5390,16 @@ get_cfg(session_t *ps, int argc, char *const *argv, bool first_pass) {
     ps->o.wintype_opacity[i] = 1.0;
   }
 
+  // Enforce LC_NUMERIC locale "C" here to make sure dots are recognized
+  // instead of commas in atof().
+  setlocale(LC_NUMERIC, "C");
+
 #ifdef CONFIG_LIBCONFIG
   parse_config(ps, &cfgtmp);
 #endif
 
   // Parse commandline arguments. Range checking will be done later.
 
-  // Enforce LC_NUMERIC locale "C" here to make sure dots are recognized
-  // instead of commas in atof().
-  setlocale(LC_NUMERIC, "C");
-
   optind = 1;
   while (-1 !=
       (o = getopt_long(argc, argv, shortopts, longopts, &longopt_idx))) {