Verifying records: What does 'provisional' mean?

When records are broken, we often first refer to them as 'provisional', but why is that and what does it mean?

The term 'provisional' means not yet verified. This is because all weather records must undergo an internationally-agreed, rigorous quality-control process, which must adhere to the World Meteorological Organisation (WMO) standards.

The WMO initially contacts the national weather service in question for the raw data, including analysis of the equipment used, calibration of the weather station and surrounding weather conditions at the time.

An international panel of scientists then review the data. The WMO validates records from all over the world and takes on average six to nine months, but can sometimes take even longer.

Only recently, during the end of January 2024, the WMO officially recognised a new temperature record for continental Europe of 48.8°C in Syracuse, Sicily, Italy, which was recorded on August 11th 2021.

This now officially breaks the previous record of 48.0°C set in Greece in 1977. An international team of scientists verified this record, marking a significant moment in Europe's climate history.

The WMO say they are currently conducting a number of other investigations, including whether Tropical Cyclone Freddy was the longest-lasting tropical cyclone on record.

Meanwhile, in the UK, we have just seen, provisionally, our warmest January day ever with a temperature of 19.9°C recorded in Achfary in north-west Scotland. However it could take several months for this record to be verified.