Rainfall has been monitored systematically in the UK since the 1860s when George Symons set up the British Rainfall Organisation, later absorbed into the Met Office, but most records made before 1960 were still in paper form.
The 65,000 paper records held in the Met Office’s National Weather Archive were scanned in 2019 and many were written in ornate script, meaning humans were needed to transcribe them.
Professor Ed Hawkins, from the National Center for Atmospheric Science at the University of Reading, said he expected the project to take months, but high public interest meant it was completed in a few days.
He said: “A lot of the dry records we have have been rewritten, and it’s only because our climate is getting wetter now.
“Just as all cold records are back in the past, so are dry records, as the climate has become wetter.
“Most of the wet records are more recent – with the exception of 1852, an extremely wet November, and I’m sure at the time they wondered what was going on.
“It would be a remarkable month for this period. Now that wouldn’t look so unusual.
The UK’s average temperature is thought to have risen by 1.5C since pre-industrial times, he said, and the additional data “helps us better understand long-term trends towards the dramatic changes that we see today”.
Data has a new life
Catherine Ross, Archivist at the Met Office, said: “The 66,000 once-inanimate figure sheets of this project have been given new life by placing data that can be interrogated and compared in the hands of scientists at the Met Office and around the world. .”
Jacqui Huntley, one of eight Rainfall Rescue volunteers based near Stranraer in Scotland who worked on the whole project, said: “I got involved because I’m British and therefore a fanatic about the weather, in particular rain. And it rains a lot where I live in Scotland.
“The data is obviously valuable to scientists, but I also loved learning about the precipitation watchers who have been so dedicated to measuring the weather day in and day out.”