diff --git a/src/util.cc b/src/util.cc
index 3cfa5fca1c..abbea3e906 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -1112,9 +1112,9 @@ double calc_next_rotate(double current, double interval, double base)
 	time_t teatime = time_t(current);
 
 	struct tm t;
-	t = *localtime_r(&teatime, &t);
+	t = *gmtime_r(&teatime, &t);
 	t.tm_hour = t.tm_min = t.tm_sec = 0;
-	double startofday = mktime(&t);
+	double startofday = timegm(&t);
 
 	if ( base < 0 )
 		// No base time given. To get nice timestamps, we round