diff --git a/custom_components/solaredgeoptimizers/coordinator.py b/custom_components/solaredgeoptimizers/coordinator.py
index 37d3ea1c..a22d5038 100644
--- a/custom_components/solaredgeoptimizers/coordinator.py
+++ b/custom_components/solaredgeoptimizers/coordinator.py
@@ -85,7 +85,7 @@ async def _async_update_data(self):
 
                 update = False
 
-                timetocheck = datetime.now() - CHECK_TIME_DELTA
+                timetocheck = dt_util.utcnow() - CHECK_TIME_DELTA    # tz-aware UTC
 
                 for optimizer in data:
                     _LOGGER.debug(
@@ -94,7 +94,13 @@ async def _async_update_data(self):
                         optimizer.lastmeasurement,
                     )
 
-                    if optimizer.lastmeasurement > timetocheck:
+                    ts = optimizer.lastmeasurement
+                
+                    # SolarEdge returns a *naive* UTC timestamp – tag it as UTC
+                    if ts.tzinfo is None:
+                        ts = ts.replace(tzinfo=timezone.utc)
+                
+                    if ts > timetocheck:
                         update = True
                         break
 
@@ -109,4 +115,4 @@ async def _async_update_data(self):
         except Exception as err:
             _LOGGER.error("Error in updating updater")
             _LOGGER.error(err)
-            raise UpdateFailed(err)
\ No newline at end of file
+            raise UpdateFailed(err)
diff --git a/custom_components/solaredgeoptimizers/sensor.py b/custom_components/solaredgeoptimizers/sensor.py
index 72ef07ed..65972e1f 100644
--- a/custom_components/solaredgeoptimizers/sensor.py
+++ b/custom_components/solaredgeoptimizers/sensor.py
@@ -4,6 +4,9 @@
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.entity import DeviceInfo
 
+from datetime import timezone
+from homeassistant.util import dt as dt_util   # HA helper, tz-aware
+
 import logging
 
 from homeassistant.components.sensor import (