The explosive thunderstorms that hit the North Island yesterday should ease but heavy rain and plummeting temperatures are forecast for the rest of the week.
WeatherWatch analyst Philip Duncan said last night's intense thunderstorms were sparked due to unusually warm temperatures.
The organisation did not receive any reports of damage, he said.
"They were explosive and some of the most vigorous thunderstorms I've seen in Auckland. Not very often do you see the more American-style thunderstorms with almost non-stop lightning.
"It was a win-win for people who like thunderstorms but without all the problems."
The centre of a low weather system would pass over New Zealand today bringing heavy showers and possible gale-force winds to western areas.
Isolated thunder and hail were also possible, Mr Duncan said.
Temperatures would drop after the low crosses the country tonight, bringing cold weather to most of the country on Thursday and Friday.
"It's going to start to feel like we're going into winter now for those who have felt like it was more like the end of summer.
"But it's not going to be too brutal and by the time we get to the weekend we're sort of getting back into more normal temperatures again."
MetService has issued a thunderstorm outlook for the North Island and upper South Island until 12pm today.
High risk areas for thunderstorms were Taranaki, Waitomo and Waikato with storms accompanied by heavy rain and strong wind gusts.
Vector spokeswoman Sandy Hodge said about 600 customers on the North Shore lost power yesterday after a transformer was struck by lightning.
The outage occurred in Belmont about 5.45pm, she said.
Power was restored to 300 customers at 7.30pm and everybody had power before 10pm.
She said any issues at the Fifa Under-20 match at Albany's North Harbour Stadium would have been a "nightmare".
"We got a warning around 3pm but these sorts of things are a bit hard to predict, how much thunder, how much lightning.
"We kind of, without much notice, have to sit back and see what happens. We got off pretty lightly."
A colder June than usual is on the cards for the rest of the month, meteorologists say.
MetService meteorologist Georgina Griffiths said the below-average temperatures expected this month were in sharp contrast to last year which had the warmest June on record for New Zealand.
The first and last weeks of the month look particularly icy and sea temperatures around the country were cooling off faster than usual, Ms Griffiths said.
"Sea temperatures are important for us because to a certain extent they influence air temperatures in our coastal regions.
"June starts pretty wet and wild, with the risk of extreme rain or snow in the mix. But, as the month progresses, the weather is likely to settle back to more typical early-winter patterns."