Nowadays, there are two very popular topics both in academic circles and in daily press: global warming and the Internet of Things (IoT). The subject of my thesis, I examined these two topics and made a prototype of an IoT device to monitor the weather. The task was to design and implement such a system at both hardware and software level. I learned about the basic problems and features that come with such systems: low power consumption, wireless energy storage and communication, convenient and automated cloud features that expand the opportunities of this system. A battery powered measuring unit with wireless communication has measured ambient environmental parameters with three different sensors and sent the data to a central unit. A central unit has collected and transmitted the measurement results to a remote cloud server where they are stored in a database to be available for a long time. In addition, I designed a graphical user interface on a touch screen display. Cloud services include managing the communication with the database and creating and displaying client-side graphical interfaces.