The North Island was lit up by more than 33,000 lightning strikes overnight.
MetService said 80 percent of the strikes were over land, which gave people a good view of electric storms.
Meteorologist Tui McInnes said a combination of humid air, a cool upper atmosphere, weak wind and warm earth created the perfect conditions for the storms.
Mr McInnes said there were a number of very heavy localised downpours, including about 50 millimetres of rain in one hour in Taranaki.
He said similar storms were expected across the North Island today.
Fire and Emergency attended 22 weather related call outs in the Auckland region, including surface flooding and two downed trees.
Hours of lightning tonight in Auckland pic.twitter.com/PWS2Awqz1V— Julian Garthwaite (@Julznova) December 14, 2018
Lightning show. Taken out our kitchen window, 12am ish. Mangere. Auckland pic.twitter.com/uiSGBBTqcI— Jenny Whiting (@jennywhiting) December 14, 2018