Nearly two-thirds of the way through a cold, wet winter in the southern regions, Niwa is predicting some relief in the form of some sunny days with temperatures over 25°C on the horizon.
Based on the strong oceanic trends, it appeared likely that the atmosphere would begin to respond in an "El Nino-like fashion" during August, Niwa National Climate Centre forecasting principal scientist Chris Brandolino said.
It meant over the next three months atmospheric pressure would be above normal to the northwest of New Zealand and below normal to the south, leading to more southwesterly quarter winds than normal across the country.
Mixed with marine heatwave conditions which remain in coastal waters, this was likely to bring above-average temperatures to the West Coast, the Southern Alps and foothills, inland Otago and Southland, he said.
Rainfall totals were equally likely to be near normal or above normal in these regions, he said.
"Southwest quarter winds are expected to increase in frequency and strength, bringing fronts and low pressure systems into the region, particularly from the second half of August onward."
Soil moisture levels and river flows were most likely to be near normal.
Along coastal Otago, rainfall totals, soil moisture levels and river flows are likely to be near normal.
"The second half of August may feature a trend towards more westerly winds, causing frequent fronts and low pressure systems near the South Island.
"Moisture may spill over the Alps into the region at times."
But on the bright side, temperatures were most likely to be above average, he said.
"More frequent westerly winds may increase the chance for hot days (with temperatures greater than 25˚C) in early-to-mid spring."
