Clear conditions with a southerly breeze are expected for the Bledisloe Cup test in Auckland on tomorrow evening.
"A warm jacket may come in handy," Mr Glassey said.
A temperature around 10C is expected at kick-off, falling to 7C by the end of the match.
Mr Glassey warned the long fine spells will lead to clear skies overnight and cool mornings. The minimum forecast for Auckland is between 3C and 5C and sheltered areas without any wind could see frosts.
"There will be a few showers in eastern places like Gisborne and Hawkes Bay," he said. "The west of the South Island is looking fine like the upper North island, but in the east there'll be a few showers."
Wellington will have showers through the weekend and cloudy periods next week. Christchurch and Dunedin should experience a few showers this weekend and cloudy periods next week.
Philip Duncan of WeatherWatch.co.nz said the prolonged fine weather would last for most of the country until next Sunday.
"The high is likely to remain in the Tasman Sea for the rest of August."
Temperatures for the next few months are likely to be warmer than usual for the east of the North Island, according to Niwa's August to October outlook. Cold snaps and frost would still be expected for parts of the country in early spring. APNZ