diff --git a/homeassistant/components/systemmonitor/coordinator.py b/homeassistant/components/systemmonitor/coordinator.py
index f6b4dadc265..ed08d6ed151 100644
--- a/homeassistant/components/systemmonitor/coordinator.py
+++ b/homeassistant/components/systemmonitor/coordinator.py
@@ -221,7 +221,9 @@ class SystemMonitorCoordinator(TimestampDataUpdateCoordinator[SensorData]):
 
         if self._initial_update:
             # Boot time only needs to refresh on first pass
-            self.boot_time = dt_util.utc_from_timestamp(self._psutil.boot_time())
+            self.boot_time = dt_util.utc_from_timestamp(
+                self._psutil.boot_time(), tz=dt_util.get_default_time_zone()
+            )
             _LOGGER.debug("boot time: %s", self.boot_time)
 
         selected_processes: list[Process] = []
diff --git a/tests/components/systemmonitor/snapshots/test_diagnostics.ambr b/tests/components/systemmonitor/snapshots/test_diagnostics.ambr
index 97d806614e1..74d8a797678 100644
--- a/tests/components/systemmonitor/snapshots/test_diagnostics.ambr
+++ b/tests/components/systemmonitor/snapshots/test_diagnostics.ambr
@@ -9,7 +9,7 @@
           'vethxyzxyz': "[snicaddr(family=<AddressFamily.AF_INET: 2>, address='172.16.10.1', netmask='255.255.255.0', broadcast='255.255.255.255', ptp=None)]",
         }),
         'battery': 'sbattery(percent=93, secsleft=16628, power_plugged=False)',
-        'boot_time': '2024-02-24 15:00:00+00:00',
+        'boot_time': '2024-02-24 07:00:00-08:00',
         'cpu_percent': '10.0',
         'disk_usage': dict({
           '/': 'sdiskusage(total=536870912000, used=322122547200, free=214748364800, percent=60.0)',
@@ -79,7 +79,7 @@
       'data': dict({
         'addresses': None,
         'battery': 'sbattery(percent=93, secsleft=16628, power_plugged=False)',
-        'boot_time': '2024-02-24 15:00:00+00:00',
+        'boot_time': '2024-02-24 07:00:00-08:00',
         'cpu_percent': '10.0',
         'disk_usage': dict({
           '/': 'sdiskusage(total=536870912000, used=322122547200, free=214748364800, percent=60.0)',