"Around Wellington they've had lots of northerlies and lots of southerlies and a lot of cloud cover.
"This week, more of the windy weather, especially over the next day or so. As this high moves away, the squash zone of those windy nor-westers moves back through."
The temperatures would also drop as the wind turned southerly later in the week, Duncan said.
"So we're not yet into the settled weather but we do think by the end of this week and coming into the weekend we should see more settled patterns starting to develop."
This is in keeping with the National Institute of Water and Atmospheric Research (NIWA) December prediction, which said conditions in the capital would settle around the middle part of the month.
Although in the first week of summer, Duncan said conditions in the capital were still imitating a spring weather pattern, with "ups and downs" with nor'westers and sou-westers.
Above normal temperatures were forecast for Canterbury, Marlborough, Hawke's Bay and Gisborne, and could reach past 30C.
The upper part of the North Island would also have humidity with added subtropical winds - Whangarei had a high of 28C on Tuesday but the Humidex temperature (or "feels like") was expected to be 32C.
