Xiaomi

The Xiaomi Smart Temperature and Humidity Monitor 3 is an indoor climate display that measures temperature and relative humidity and shows the readings locally together with time/date information. The official model is MJWSD05MMC.

Xiaomi specifies Bluetooth 5.0 Low Energy connectivity, CR2450 battery power and a 79.6 × 70.2 × 14.5 mm body. The documented measurement ranges are 0–60 °C and 0–99% relative humidity.

The monitor can be added to the Xiaomi Home/Mi Home app. A compatible Bluetooth or Bluetooth Mesh gateway is required for remote data synchronization and automations such as turning on a heater or humidifier when a threshold is reached.

The product sold as “Mijia Smart Thermometer 3” corresponds to Xiaomi’s Smart Temperature and Humidity Monitor 3 specifications. This is a monitoring device rather than a control switch, and it should not be treated as a calibrated laboratory instrument.

Temperature and humidity monitors work best away from direct sunlight, heating outlets, open windows and other local influences that can distort room readings. Bluetooth models can be read nearby without a gateway, while continuous remote history and automations depend on the documented gateway path. These displays are intended for household environmental monitoring rather than calibrated laboratory measurement.

The local display provides an immediate reading, while the app/gateway path is useful for trends and automations. A practical setup is to watch how the room changes over several days before choosing automation thresholds, rather than reacting to a single reading. If several monitors are used, place them in representative locations so that each device reflects the room or zone it is intended to manage.