diff --git a/homeassistant/components/tomorrowio/sensor.py b/homeassistant/components/tomorrowio/sensor.py
index aba5b44f28418..7ccb4f673cde1 100644
--- a/homeassistant/components/tomorrowio/sensor.py
+++ b/homeassistant/components/tomorrowio/sensor.py
@@ -18,6 +18,7 @@
     SensorDeviceClass,
     SensorEntity,
     SensorEntityDescription,
+    SensorStateClass,
 )
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
@@ -295,6 +296,7 @@ def convert_ppb_to_ugm3(molecular_weight: int | float) -> Callable[[float], floa
     TomorrowioSensorEntityDescription(
         key=TMRW_ATTR_UV_INDEX,
         name="UV Index",
+        state_class=SensorStateClass.MEASUREMENT,
         icon="mdi:sun-wireless",
     ),
     TomorrowioSensorEntityDescription(