<![CDATA[ABSTRACT The significant decrease in corn production in North Sulawesi Province from 2020 (174 thousand tons) to 2023 (88 thousand tons) indicates critical factors that need to be managed, one of which is the microclimate condition, encompassing air temperature and humidity. Fluctuations in temperature and humidity directly affect transpiration rates, photosynthesis, nutrient uptake, and the risk of pest and disease attacks on corn plants. Therefore, this research aims to develop and implement an IoT-based microclimate measurement instrument as an effort to achieve optimal corn production yields. The research methodology includes the design of a hardware integrated with temperature and humidity sensors and the microcontroller, as well as the design of software for data transmission to a cloud server via internet connection. The collected data is then presented in real-time through sheet. The instrument validation test was conducted by comparing the measurement instrument data against the data from BMKG using the Pearson correlation test (r).Results showed a very strong correlation coefficient: air temperature (r=0.857); air humidity (r=1); and soil moisture (r=0.864). This high correlation value proves that the developed instrument is compliant with the standard. Results show that the IoT-based temperature and humidity measurement instrument was successfully developed. Keywords: Corn, IoT, measurement, air temperature, humidity, Tomohon]]>
