Rainfall total is expected to be near the normal range but Niwa principal climate scientist Brett Mullan said there would be longer dry spells for Tauranga.
"What we are looking at is certainly warmer than normal conditions in the Bay of Plenty, but rainfall is about normal overall. That doesn't mean more rain. You could have a very wet month followed by a very dry month," Dr Mullan said.
"Another thing that is of note is the temperature of the Tasman Sea is 2 degrees above normal.
"Weather systems coming to New Zealand from Australia can pick up extra moisture from the warm air so there's a good evaporation of water in the air as it comes through."
When rain did arrive in the region it was likely to be more intense than normal because of this, Dr Mullan said.
Metservice meteorologist Dan Corbett said after this weekend's cold spell and winter being warmer than normal, it was hard to predict other extreme weather events. Already this year the region has experienced drought and flooding.
"Things that influence seasons such as El Nino or La Nina, they are sitting on the fence at the moment, so we don't really know how things will go at this stage," he said.
Copenhagen Cones manager Shannon Peters was looking forward to a warmer winter. It meant a better chance at selling more icecream, she said.
"I like the sound of that, just so people can get out and enjoy themselves more. If it's not cold or raining," she said.
Ms Peters said there was a notable difference in demand at the icecream store between seasons.
"When it's cold it's not so bad as when it's raining. That's when you can park pretty much anywhere at the Mount."
Forecast
TODAY: Mostly cloudy, chance morning drizzle. Light winds. High of 21C, low of 15C.
SATURDAY: Rain developing in the afternoon. Northeasterlies. High of 20C, low of 13C.
SUNDAY: Rain easing to odd shower. Strengthening westerlies. High of 10C, low of 9C.
MONDAY: Shower or two. Westerlies easing. High of 17C, low of 9C.
TUESDAY: Showers. Southwesterlies. High of 19C, low of 10C.
WEDNESDAY: Showers with light winds. High of 19C, low of 9C.
THURSDAY: Dry. Little wind. High of 19C, low of 10C.