diff --git a/sternwarte-homeassistant-integration/custom_components/sternwarte/__pycache__/const.cpython-312.pyc b/sternwarte-homeassistant-integration/custom_components/sternwarte/__pycache__/const.cpython-312.pyc
new file mode 100644
index 0000000..4b7df88
Binary files /dev/null and b/sternwarte-homeassistant-integration/custom_components/sternwarte/__pycache__/const.cpython-312.pyc differ
diff --git a/sternwarte-homeassistant-integration/custom_components/sternwarte/__pycache__/coordinator.cpython-312.pyc b/sternwarte-homeassistant-integration/custom_components/sternwarte/__pycache__/coordinator.cpython-312.pyc
index 7485788..88c6fa1 100644
Binary files a/sternwarte-homeassistant-integration/custom_components/sternwarte/__pycache__/coordinator.cpython-312.pyc and b/sternwarte-homeassistant-integration/custom_components/sternwarte/__pycache__/coordinator.cpython-312.pyc differ
diff --git a/sternwarte-homeassistant-integration/custom_components/sternwarte/const.py b/sternwarte-homeassistant-integration/custom_components/sternwarte/const.py
index 14e53e1..0e061ad 100644
--- a/sternwarte-homeassistant-integration/custom_components/sternwarte/const.py
+++ b/sternwarte-homeassistant-integration/custom_components/sternwarte/const.py
@@ -17,6 +17,7 @@ DEFAULT_PASSWORD = "sowo2009"
 
 UPDATE_INTERVAL_SECONDS = 1
 POWER_ON_DELAY_SECONDS = 30
+OPEN_SCHEDULE_MAX_AGE_SECONDS = 6 * 60 * 60
 WIND_INTERVAL_SECONDS = 30
 WIND_COUNTER_INDEX = 4
 WIND_FACTOR = (2 / 3) * 3.6
diff --git a/sternwarte-homeassistant-integration/custom_components/sternwarte/coordinator.py b/sternwarte-homeassistant-integration/custom_components/sternwarte/coordinator.py
index cd15afb..76da6d5 100644
--- a/sternwarte-homeassistant-integration/custom_components/sternwarte/coordinator.py
+++ b/sternwarte-homeassistant-integration/custom_components/sternwarte/coordinator.py
@@ -23,6 +23,7 @@ from .const import (
     CONF_PASSWORD,
     CONF_PORT,
     DEFAULT_NAME,
+    OPEN_SCHEDULE_MAX_AGE_SECONDS,
     POWER_ON_DELAY_SECONDS,
     ROOF_COUNTER_CLOSE_INDEX,
     ROOF_COUNTER_OPEN_INDEX,
@@ -586,6 +587,24 @@ class SternwarteDataUpdateCoordinator(DataUpdateCoordinator[SternwarteState]):
                         changed = True
 
             open_power_on_at = self._schedule_datetime(self.schedule.open_power_on_at)
+            open_at = self._schedule_datetime(self.schedule.open_at)
+            if (
+                open_at is not None
+                and not self.schedule.open_done
+                and now - open_at > timedelta(seconds=OPEN_SCHEDULE_MAX_AGE_SECONDS)
+            ):
+                LOGGER.warning(
+                    "Veraltete Öffnungsplanung verworfen: open_at=%s now=%s",
+                    open_at.isoformat(),
+                    now.isoformat(),
+                )
+                self.schedule.open_at = ""
+                self.schedule.open_done = True
+                self.schedule.open_power_on_at = ""
+                changed = True
+                open_power_on_at = None
+                open_at = None
+
             if open_power_on_at is not None and not self.schedule.open_done and now >= open_power_on_at:
                 if self._is_roof_open(state):
                     LOGGER.info("Automatisches Öffnen bereits erfüllt")
@@ -645,7 +664,6 @@ class SternwarteDataUpdateCoordinator(DataUpdateCoordinator[SternwarteState]):
                         )
                         changed = True
 
-            open_at = self._schedule_datetime(self.schedule.open_at)
             if open_at is not None and not self.schedule.open_done and now >= open_at and not self.schedule.open_power_on_at:
                 if self._is_roof_open(state):
                     LOGGER.info("Automatisches Öffnen übersprungen, Dach ist bereits offen")