diff --git a/homeassistant/components/airnow/const.py b/homeassistant/components/airnow/const.py
index 34b1f4392bc..137c8f1efad 100644
--- a/homeassistant/components/airnow/const.py
+++ b/homeassistant/components/airnow/const.py
@@ -9,8 +9,9 @@ ATTR_API_CAT_DESCRIPTION = "Name"
 ATTR_API_O3 = "O3"
 ATTR_API_PM25 = "PM2.5"
 ATTR_API_POLLUTANT = "Pollutant"
-ATTR_API_REPORT_DATE = "HourObserved"
-ATTR_API_REPORT_HOUR = "DateObserved"
+ATTR_API_REPORT_DATE = "DateObserved"
+ATTR_API_REPORT_HOUR = "HourObserved"
+ATTR_API_REPORT_TZ = "LocalTimeZone"
 ATTR_API_STATE = "StateCode"
 ATTR_API_STATION = "ReportingArea"
 ATTR_API_STATION_LATITUDE = "Latitude"
diff --git a/homeassistant/components/airnow/coordinator.py b/homeassistant/components/airnow/coordinator.py
index 7a4ad46cd82..e89afc2f7ce 100644
--- a/homeassistant/components/airnow/coordinator.py
+++ b/homeassistant/components/airnow/coordinator.py
@@ -20,6 +20,7 @@ from .const import (
     ATTR_API_POLLUTANT,
     ATTR_API_REPORT_DATE,
     ATTR_API_REPORT_HOUR,
+    ATTR_API_REPORT_TZ,
     ATTR_API_STATE,
     ATTR_API_STATION,
     ATTR_API_STATION_LATITUDE,
@@ -83,6 +84,7 @@ class AirNowDataUpdateCoordinator(DataUpdateCoordinator):
                 # Copy Report Details
                 data[ATTR_API_REPORT_DATE] = obv[ATTR_API_REPORT_DATE]
                 data[ATTR_API_REPORT_HOUR] = obv[ATTR_API_REPORT_HOUR]
+                data[ATTR_API_REPORT_TZ] = obv[ATTR_API_REPORT_TZ]
 
                 # Copy Station Details
                 data[ATTR_API_STATE] = obv[ATTR_API_STATE]
diff --git a/homeassistant/components/airnow/sensor.py b/homeassistant/components/airnow/sensor.py
index c83232c273a..f9d35d50810 100644
--- a/homeassistant/components/airnow/sensor.py
+++ b/homeassistant/components/airnow/sensor.py
@@ -3,6 +3,7 @@ from __future__ import annotations
 
 from collections.abc import Callable
 from dataclasses import dataclass
+from datetime import datetime
 from typing import Any
 
 from homeassistant.components.sensor import (
@@ -13,6 +14,7 @@ from homeassistant.components.sensor import (
 )
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
+    ATTR_TIME,
     CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
     CONCENTRATION_PARTS_PER_MILLION,
 )
@@ -21,6 +23,7 @@ from homeassistant.helpers.device_registry import DeviceEntryType, DeviceInfo
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.typing import StateType
 from homeassistant.helpers.update_coordinator import CoordinatorEntity
+from homeassistant.util.dt import get_time_zone
 
 from . import AirNowDataUpdateCoordinator
 from .const import (
@@ -29,6 +32,9 @@ from .const import (
     ATTR_API_AQI_LEVEL,
     ATTR_API_O3,
     ATTR_API_PM25,
+    ATTR_API_REPORT_DATE,
+    ATTR_API_REPORT_HOUR,
+    ATTR_API_REPORT_TZ,
     ATTR_API_STATION,
     ATTR_API_STATION_LATITUDE,
     ATTR_API_STATION_LONGITUDE,
@@ -78,6 +84,12 @@ SENSOR_TYPES: tuple[AirNowEntityDescription, ...] = (
         extra_state_attributes_fn=lambda data: {
             ATTR_DESCR: data[ATTR_API_AQI_DESCRIPTION],
             ATTR_LEVEL: data[ATTR_API_AQI_LEVEL],
+            ATTR_TIME: datetime.strptime(
+                f"{data[ATTR_API_REPORT_DATE]} {data[ATTR_API_REPORT_HOUR]}",
+                "%Y-%m-%d %H",
+            )
+            .replace(tzinfo=get_time_zone(data[ATTR_API_REPORT_TZ]))
+            .isoformat(),
         },
     ),
     AirNowEntityDescription(
diff --git a/tests/components/airnow/snapshots/test_diagnostics.ambr b/tests/components/airnow/snapshots/test_diagnostics.ambr
index 8041cb55692..80c6de427ca 100644
--- a/tests/components/airnow/snapshots/test_diagnostics.ambr
+++ b/tests/components/airnow/snapshots/test_diagnostics.ambr
@@ -8,6 +8,7 @@
       'DateObserved': '2020-12-20',
       'HourObserved': 15,
       'Latitude': '**REDACTED**',
+      'LocalTimeZone': 'PST',
       'Longitude': '**REDACTED**',
       'O3': 0.048,
       'PM10': 12,