I have two DHT22 sensor in the same room, one off them working with an ESP8266-12E (NODE-MCU) and the other working with an ESP8266-01. Both communicate with Node-RED via MQTT (No problems here). The “problem” is they show a 2,5 degrees C difference and more than 20% difference on the humidity readings. They use the same code to calculate and show the readings.
Are the DHT22 this innacurate ? Any thoughts are welcome.
Continuing the tests, I mounted 4 other DHT22s with an ESP8266-NodeMCU.
With the following results:
The results are reasonable. The temperature readings within more or less 1% and all but one of the humidity readings being off the 2% tolerance.
Probably the DHT22 that was giving rogue readings is defective.
Sometimes if the sensor is subjected to very high levels of humidity, it will take some time until it is able to detect low levels again.
However, I see that in your case, it is the other way around. So, probably there’s something wrong with that sensor.