The size of the drops of rain can be observed on impact with surfaces such as the amount of spread on cement, the length of the drops when striking vertical surfaces especially windows, or how far they rebound when they hit surfaces such as metal or water. Drops of rain also appear larger and more frequent than normal on windscreens whilst driving against the rain. Rainbows are another method that can be used to observe if rain is falling. Occasionally, rain mixed with dust has its own distinct scent especially after a long hot day. If heavy rain occurs suddenly, as is the case with many thunderstorms, it can be heard approaching from a few hundred metres away striking other house or shed roves.
Rain gauges are easy to erect and maintain.
They are usually not very expensive to purchase. They work on a principal that a flat area of land will fill with the amount of water measured in the rain gauge. If you experience a thunderstorm that produces deep hail or live in an area where it snows, it is possible to estimate approximately the amount of precipitation it represents using a special technique. However, it is best to consult meteorological organisations in your country on measurements of the various forms of precipitation and the appropriate times to take measurements.