Back in 1992, the former Meteorological Service split, with MetService taking on daily forecasts and Niwa focusing on climate research and long-term predictions.
Independent forecaster Philip Duncan from WeatherWatch has been critical of the agencies in the past, and told Morning Report that the merger makes sense.
"It makes sense for the New Zealand government to no longer have two opposing authorities in the weather area. So this is a smart decision, but there is still a lot to work out as to whether or not this is going to be good in the long run for the MetService brand, and that's still a big unknown."
Niwa and MetService have not always seen eye to eye over the years since they split apart.
"There is this long-running sort of rivalry between the two organisations," Duncan said. "Niwa started quite aggressively competing against MetService. It had no ministerial approval, nobody in Cabinet really knew about it. This happened under the John Key government, and everyone was baffled.
"I've never met a politician that understood why Niwa got into doing weather, but they did."
Duncan said there may be cultural challenges in merging the agencies.
"There's going to be a bit of a tough time for the MetService meteorologists to be integrated into the Niwa sort of empire, because Niwa is a very big empire within our government agencies."
The merger was recommended in the Weather Forecasting System Review, which the government commissioned from the Sapere research group last year after the severe weather events.
Niwa said on Thursday it was pleased by the announcement, and it anticipated legislation will be introduced in mid-2025. The timing would depend on the progress of the legislation through Parliament and the process that followed.
Duncan predicted there would be some job losses in the merger.
"I'm assuming there will be, but here's the big question. Niwa has brought in all these new forecasters from overseas, they've set up this new department, then you've got the MetService team as well.
"I don't think there's enough work for all of them unless they are winning a lot of commercial contracts, which Niwa does win a lot of."
Duncan said if the agencies merge there would clearly be a monopoly of weather services. In the past he has called for much more transparency with weather data.
"I'm hoping that the Commerce Commission having to be involved in that is actually going to force Niwa and MetService… to create much better, more open services, like we see in Australia, Canada and the rest of the modern world."
Neither MetService, Niwa nor Science Minister Judith Collins were available for comment on Friday morning.
