Niwa climate scientists are predicting the next three months will be warmer than normal in Otago and Southland.
Niwa National Climate Centre forecasting principal scientist Chris Brandolino said sea surface temperatures warmed across the equatorial Pacific this month and the El Nino weather pattern was expected to continue between April and June.
While the coming weeks were expected to bring mixed air flows, "higher pressure than normal" was forecast to develop in the northern Tasman Sea, along with "lower pressure than normal" south of New Zealand.
"This is expected to result in more westerly quarter winds than normal, particularly during the second half of the coming season.
"Air temperatures are forecast to be above average in the east of the South Island and about equally likely to be above average or near average in all remaining regions of New Zealand.
"However, cold snaps and frosts are likely to occur, particularly in colder locations, as the season progresses."
He said rainfall was about equally likely to be above normal or near normal on the West Coast, Alps and foothills, inland Otago and Southland; and about equally likely to be below normal or near normal in East Otago.
"Well-above-average coastal and Tasman Sea surface temperatures, including marine heatwave conditions, are forecast to have a strong influence on regional temperatures and may contribute to significant rain events."
Soil moisture levels and river flows were most likely to be below normal in the east of the South Island, and above normal for the west and south of the South Island.
