The Weather Bureau in WA says it is increasingly having to defend itself against claims it is "cooking the books" as part of a conspiracy to prove the State's weather is changing.
As the chapter closed at the weekend on one of Perth's driest and warmest summers, the bureau said resources were being wasted as staff answered questions about the legitimacy of its record keeping.
Some of the claims being made against the Federal Government-controlled organisation were that it was deliberately moving gauges to areas where it rained less.
Other claims asserted that changes in equipment could have skewed meteorological data to favour the view that Perth and the South West's climate was drying and warming.
Neil Bennett, a senior forecaster with the bureau, said there was unprecedented demand for its services and its huge store of information.
"But the flip of that is you find yourself having to defend your record keeping," Mr Bennett said.
"You find that you're spending time answering people who come to you and say, 'You're cooking the books, you're mistreating the data, you're moving your sites around and you're adding fudge factors into the narrative you want to drive'.
"People, not so much in the regional offices but in head office, are having to do a lot of that sort of work.
"They're finding that their work is being diverted from monitoring the real data to go back and answering questions about, 'Why did you move that particular weather station in 1992, what happened when you changed the thermometers, why did you do that?'"
Perth has recorded a 15-20 per cent fall in annual rainfall compared with the long-term average and a savage decline in run-off into the city's dams and aquifers.
It is also warming, according to bureau figures showing that mean temperatures in Perth have risen more than 1C since 1910.
The Department of Water said the availability of water for public open space, typically sourced from groundwater, was now so tight that it was clamping down on how it could be used.
"Sweeping entrance statements and huge stretches of lawn that are never walked on are things of the past," the department's director-general Maree De Lacey said.