The Oldest Weather Records Still Standing

The oldest daily weather record standing in this build dates from 1763: Milan recorded -2.4 C (27.7 F) on 13 March 1763, and it has stood for 263 years. Old records are less common than you might think, and their age says as much about the station as about the weather.

How we find them

For every station and every calendar day we know the date of the standing record. Sorting by age gives the oldest standing list. We also track the other direction: the longest a record stood before it fell. That list is led by Milan, where a record of 1 November 2006 stood for 241 years before it was beaten. Near misses are the third list: records that a recent year came close to, and the gap in each case. All three are on the longevity page.

Why old records are rare

A record survives only if no later year beats it. On any given day of the year, a station’s chance of setting a record falls as its history lengthens, so at a station with a long history each year is less likely to top the old value. That would suggest many very old records. In practice the earliest years of most series are patchy, so the oldest records come from the few stations with a long, complete history, and the list is short.

What age does not tell you

An old record is not necessarily a great one. A record from a station that only began measuring a few years earlier is old but not remarkable. The significance score weighs age with margin and length of record for that reason. Age also depends on the station: a record set at a site that later moved may be threaded from an earlier site, as described in how station moves affect city records.

How to use the list

Treat the list as a way in. Pick a station, open its page and look at how many of its daily records come from before 1950. Compare with the ratio of highs to lows to see whether recent years are taking over. The sources page lists the observation data these figures come from, and how we count records explains what qualifies.