HISTORICAL RECORDS, MODERN SCIENCE
Humanity has been gathering weather data for centuries. In fact, some of the oldest records, found in places like China, Japan and Korea, date back thousands of years, documenting rainfall, snow patterns and the timing of flowers blossoming or ice melting.
Rain and snow gauges are relatively simple devices. Precision instruments such as thermometers and barometers only came about after the 1600s, but even then, they did not follow modern scales of measurement.
The biggest technological shift was in the 1800s. Weather records became far more reliable and standardised thanks to the rise of modern measuring instruments and international agreements enforcing the adoption of recognised scales.
Whenever scientists make declarations about the hottest year on record, they use weather records that date to the 1880s, when measuring instruments and scales are considered more compatible with modern quality control and calibration methods.
However, historical weather records are not always easy for scientists to access. Scattered across archives, institutions and private collections around the world, these datasets are hidden gems waiting to be uncovered.
