diff --git a/pool.js b/pool.js
index a99c277..6cb7f52 100644
--- a/pool.js
+++ b/pool.js
@@ -92,6 +92,14 @@ function update_new_day() {
   print("[POOL] update_new_day", status.tick_day);
   status.temp_yesterday = status.temp_today;
   status.temp_today = null;
+
+  Shelly.call(
+    "KVS.Set",
+    { key: "pool.temp_yesterday", value: status.temp_yesterday },
+    function (result) {
+      print("[POOL] KVS set: ", JSON.stringify(result));
+    }
+  );
 }
 
 // call a chain of API calls