diff --git a/js/component/card/runtime_sensor_detail.js b/js/component/card/runtime_sensor_detail.js
index f24417e..aa3196f 100644
--- a/js/component/card/runtime_sensor_detail.js
+++ b/js/component/card/runtime_sensor_detail.js
@@ -116,7 +116,7 @@ beestat.component.card.runtime_sensor_detail.prototype.decorate_contents_ = func
   // Don't go before there's data.
   required_begin = moment.max(
     required_begin,
-    moment(thermostat.first_connected)
+    moment.utc(thermostat.first_connected)
   );
 
   // Don't go after now.
diff --git a/js/component/card/runtime_thermostat_detail.js b/js/component/card/runtime_thermostat_detail.js
index a491aa7..cade6d6 100644
--- a/js/component/card/runtime_thermostat_detail.js
+++ b/js/component/card/runtime_thermostat_detail.js
@@ -135,7 +135,7 @@ beestat.component.card.runtime_thermostat_detail.prototype.decorate_contents_ =
   // Don't go before there's data.
   required_begin = moment.max(
     required_begin,
-    moment(thermostat.first_connected)
+    moment.utc(thermostat.first_connected)
   );
 
   // Don't go after now.