In order to forecast certain microclimatic parameters in a room, such as relative humidity, it is necessary to collect a large amount of data. For this reason, an electronic system for providing comfortable conditions in a room has been developed, which is based on the becoming largely popular Internet of Things (IoT) technology. On the basis of the obtained data, the future change of the relative humidity in a room can be forecasted, which aims to ensure the health and well-being of its inhabitants. It should be noted that working with large datasets requires more sophisticated methods for prediction, and for this reason, this paper presents results obtained from a modified ordinary differential equation approach for forecasting relative humidity. For the purposes of the study, a program code was developed in Matlab. The resulting predicted relative humidity values are comparable to actual measured values, which would help to improve indoor air quality and provide thermal comfort to occupants.