A team of Niwa forecasters met on Monday to develop their spring models, Mr Brandolino said.
"We look at international and local models ... we had a two-hour discussion about the data and considered the big picture."
The scientists also decided there was little chance of a spring El Nino developing. Fast-forward three months though, he said, and there would be a 70 per cent chance of the weather system developing over summer.
El Nino would bring high rainfall to the west of the country, with mildly warmer and dryer conditions to the east.
In the more immediate future, the upper North Island would have only a brief reprieve from the rain before it returns.
MetService forecaster Hannah Moes said today should follow the lead of yesterday's sunshine, but more rain should set back in tomorrow.
"On Thursday, we have another low approaching the country."
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Warm, but wet -- Niwa's outlook for spring
* 45 per cent chance of above-average temperatures and rainfall in the upper North Island.
* 40 per cent chance of average temperatures and rainfall.
* 15 per cent chance of below-average temperatures and rainfall.