diff --git a/src/esp_sensors/dht22.py b/src/esp_sensors/dht22.py
index 49b755d..9b6525f 100644
--- a/src/esp_sensors/dht22.py
+++ b/src/esp_sensors/dht22.py
@@ -129,7 +129,7 @@ class DHT22Sensor(TemperatureSensor, HumiditySensor):
 
     def read_humidity(self) -> float:
         """
-        Read the current humidity.
+        Just returns the _last_humidity. If reading the sensor is needed, call read_temperature first.
 
         Returns:
             The humidity reading as a float (percentage)
diff --git a/tests/test_dht22_sensor.py b/tests/test_dht22_sensor.py
index 6e77531..500001c 100644
--- a/tests/test_dht22_sensor.py
+++ b/tests/test_dht22_sensor.py
@@ -113,7 +113,7 @@ def test_dht22_read_updates_both_values():
     old_temp = sensor._last_reading
     sensor._last_humidity = None
 
-    # Reading humidity should not change temperature
+    # Reading humidity should not change anything by itself
     humidity = sensor.read_humidity()
     assert sensor._last_reading == old_temp
-    assert humidity is not None
+    assert humidity is None