diff --git a/homeassistant/components/smartthings/climate.py b/homeassistant/components/smartthings/climate.py
index f2f9479584c..c594ca237a4 100644
--- a/homeassistant/components/smartthings/climate.py
+++ b/homeassistant/components/smartthings/climate.py
@@ -307,7 +307,7 @@ class SmartThingsThermostat(SmartThingsEntity, ClimateEntity):
         return None
 
     @property
-    def target_temperature_low(self):
+    def target_temperature_low(self) -> float | None:
         """Return the lowbound target temperature we try to reach."""
         if self.hvac_mode == HVACMode.HEAT_COOL:
             return self.get_attribute_value(