diff --git a/libs/temporal/temporal/beats.h b/libs/temporal/temporal/beats.h
index b7cb0694c5..2ee0ca331e 100644
--- a/libs/temporal/temporal/beats.h
+++ b/libs/temporal/temporal/beats.h
@@ -27,6 +27,7 @@
 
 #include <iostream>
 #include <limits>
+#include <sstream>
 
 #include "pbd/failed_constructor.h"
 #include "pbd/integer_division.h"