How accurate is historical weather data?

With many records being broken in recent months we often see a baseline point centered in the 1800s. So, why is this and are older records accurate?

While it is true that modern meteorology is still relatively young in the grand scheme of things, many of the instruments used today have a long history. Thermometers, for example, were developed by ancient Greeks before being widely adopted in the 17th century.

It wasn’t until the 1600s that the standardized thermometer of today came along.

The main issue with historic records is that many have been lost or were handwritten. Meaning there is no global, digitized record of weather readily available. That is not to say that it does not exist, ship logs hold records of conditions encountered on their travels but remain inaccessible.

It just so happens that of all the accurate data we have available today, the earliest reliable starting point is in the year 1880.

From here we also have insights from ocean sediment, tree rings, ice cores, and coral which can unveil ancient climates and events, helping build the picture of our planet going back thousands of years.

Meteorologists and volunteers are working around the world to digitize old weather data, eventually, we will likely see the benchmark of 1880 fall to an earlier date.