diff --git a/homeassistant/components/wemo/fan.py b/homeassistant/components/wemo/fan.py
index 81065cf8108..1d2c2c9252d 100644
--- a/homeassistant/components/wemo/fan.py
+++ b/homeassistant/components/wemo/fan.py
@@ -86,6 +86,7 @@ class WemoHumidifier(WemoBinaryStateEntity, FanEntity):
 
     _attr_supported_features = FanEntityFeature.SET_SPEED
     wemo: Humidifier
+    _last_fan_on_mode: FanMode
 
     def __init__(self, coordinator: DeviceCoordinator) -> None:
         """Initialize the WeMo switch."""
diff --git a/requirements_test.txt b/requirements_test.txt
index 2b0cf62bbfd..54086086c38 100644
--- a/requirements_test.txt
+++ b/requirements_test.txt
@@ -11,7 +11,7 @@ astroid==2.15.4
 coverage==7.2.4
 freezegun==1.2.2
 mock-open==1.4.0
-mypy==1.2.0
+mypy==1.3.0
 pre-commit==3.1.0
 pydantic==1.10.7
 pylint==2.17.4