It's not the longest climate dataset, but it may be the longest directly recorded by humans. All of these types of data are climate proxies (alternate indicators we can use to gain information about historic climates), the longest of which are ice core measurements.

[–] teyrnon@sh.itjust.works 6 points 5 days ago (1 children)

Idk, egyptian priests kept records of the groundwater levels to predict the nile flood times to keep the peasants in check, and that could count as a climate dataset that far predates and is longer than this.

[–] sukhmel@programming.dev 4 points 5 days ago (1 children)

Do floods correlate well with the climate there, or are they affected by something else, too? If they are not much affected, then that could be a dataset indeed

[–] teyrnon@sh.itjust.works 1 points 5 days ago

Indeed they could, any core sample of the earth could, and long has, been a record of climatic conditions.