The Australian Government has returned two decades of weather data to East Timor, after it was rescued by a Darwin meteorologist amid civil unrest during the small island nation's move to independence.

Meteorologist Sam Cleland arrived in Dili in 1999 to help restore weather services in the country, and was shocked to find 20 years of records left in an abandoned office.

"There was a lot of paper records strewn over the floor, a foot deep in places, I spent the next few hours sifting through trying to gather what I could", he said.

He then spent hours collecting what papers he could before taking them to the airport and sending them to Darwin for safekeeping.

The records are being returned in their original paper form to the country's national archives, but also in a digitised form so local agencies and scientists can access the data for research and modelling.

Australian and East Timorese scientists say the 20 years of records fill an important gap in knowledge about the country's weather and its climate.

They say it has been difficult for Timor to understand potential climate change and impacts because of the missing information.

The digitisation of the records is also part of a broader project to convert all of Timor's weather data from paper to electronic format.

There are still decades of data missing from the periods when Portugal and Indonesia colonised the small island nation.

East Timor has applied to Portugal and Indonesia to obtain those records.