Farmers are being warned they may be in for a dry summer but Niwa says it's not sure how bad things will get.
El Niño is already on it's way, bringing windy, cold and dry conditions, with a low chance of rain.
Niwa principal forecasting scientist Chris Brandolino told Morning Report farmers may need to start preparing because soil moisture levels are already below average.
"The fact that things are already on the dry side and the fact that rainfall, at least above normal rainfall is pretty unlikely, that's something Niwa is watching."
He said there has already been a big "dry" throughout the South Island, with some farmers turning on their irrigation systems early to keep the soil moist.
Warm temperatures aren't expected to be a theme for the upcoming three-month period, he said.
"But that doesn't mean there won't be the odd warm spell."