Currently the appearance of really low power wireless transceivers at very low prices is motivating the development of many wireless applications out of the industrial field, which up to now turn to be large in size and expensive. We present the design of a tiny and low cost Wireless Weather Station to measure accurate temperature (±0.1ºC), relative humidity (±3%), light intensity and atmospheric pressure (±0.8hPa). These direct climatic variables and others indirectly attainable, like the dew-point, wind chill, etc, are readable through a web page. The chosen sensors are factory calibrated and have a digital interface. The Weather Sensor Nodes are able to achieve ultra low power consumption (40µA average), allowing a single super capacitor to power them for 52 days.