The more traditional interpretation tells us that it indicates a very high probability of rain or storms. These are the data it uses to make predictions: heat produces water vapor, water vapor has a lower density than air, then humid air is less dense than dry air. In addition, solid, liquid or gaseous bodies, when heated, expand, then have a lower density. For these reasons the hot air that contains water vapor from evaporation from the earth, water, plants and living things rises in the atmosphere. The rising water vapor is affected by the temperature of the atmosphere, which decreases an average of 0.6 ° C every 100 m. When the water vapor reaches the colder areas, the water vapor condenses and forms clouds that can be water droplets or ice crystals, in the case of snow or hail. When the drops of water are united to the highest zone of the atmosphere by contact when cooling, they weigh so much that they fall, causing the precipitations in the form of rain, snow or hail.

The hood accompanies the movement of the arm, which will cover the head depending on the prediction. It must be placed in a dry and ventilated place, so that, free from the influence of stale air, it can work in perfect harmony with the atmospheric variations outside. It has a hole to hang it on the wall. The average notice period with which you indicate these variations is 24 hours.
Includes instructions for use and adjustment.
Measures: 33.5 x 24.2 x 2.9 cms.
Material: cardboard and metal mechanism.
Location: in a place outside and covered from the rain so that it does not get wet.