Taking Direct Measurements

Observations taken with instruments are known as direct measurements. Instruments for collecting direct weather and climate data such as thermometers, rain gauges, and barometers had to be invented and then improved over time. Surface observations based on instruments have only been available for the last few centuries and continuous records of temperature and precipitation are rare. Data from the upper air has only been collected since the 1930s.

Sources: Cooperative Weather Observers | NOAA