Weather is the state of the massive gaseous layer that envelopes our planet. A number of different factors influence what goes on in the atmosphere, so, it makes the weather difficult to predict.
One important relationship in our atmosphere is that of air temperature and air pressure. When air heats up, it rises. When it cools, it descends. These two factors play a key role in air circulation and cloud formation.
THERMOMETERS are used to measure AIR TEMPERATURE. BAROMETERS are used to measure AIR PRESSURE. HYDROMETERS are used to measure MOISTURE.
When water falls to the ground in the form of precipitation, RAIN COLLECTORS provide us with an accurate measurement, and finally, we need to know which way the wind is blowing to know where weather is headed. An ANEMOMETER performs this task.