The microclimate inside a greenhouse, particularly temperature and humidity, requires regular monitoring to maintain conditions that support optimal plant growth. Manual monitoring can be time-consuming, prone to human error, and may delay decision-making. This research developed an Internet of Things (IoT)-based monitoring system using an ESP32 microcontroller and DHT22 sensor to measure microclimate fluctuations in a simulated greenhouse environment. The measurement data were transmitted through a Wi-Fi network and displayed in real time on the Blynk app dashboard on the user's smartphone. Testing was conducted in a simulation scenario to evaluate sensor readings, system stability, and the continuity of data display. The results showed that measurement data were automatically updated on the dashboard with an average delay of 1 to 3 seconds. The ESP32-based system provides a simple, affordable, and accessible solution for greenhouse microclimate monitoring and can serve as a basis for further development toward an automated monitoring and control system.