MetService has issued heat alerts for 18 towns and cities across the country today amid soaring temperatures.

Kaitaia, Paihia, Russell, Auckland, Hamilton, Tokoroa, Te Kūiti, Whakatāne, Taupō, Taumaranui, Napier, Masterton, Whanganui, Palmerston North, Levin, Wellington, Blenheim and Kaikōura all received heat alerts on Monday.

Auckland is currently seeing the highest temperature, with 29.7C recorded on the North Shore at midday.

Meteorologist Clare O’Connor said the warmer air over the North Island is the result of a low pressure system which moved down from the north, dragging warm humid air with it.

However, O’Connor added that “a respite is on the way, with a cold southwesterly change approaching the country, reaching the far south of the South Island late tonight, sweeping up the country to reach the lower North Island midday Tuesday before crossing the rest of the North Island in the later half of Tuesday”.

This will cause single digit temperatures overnight for most of the South Island and “halve” overnight temperatures for the North Island, she said.

Temperatures are then expected to return to the average for this time of year by the end of the week.

MetService is trialling heat alerts from November through March in an attempt to reduce health impacts from hot weather.

“Extreme heat during summer can be draining and have an impact on people’s daily lives, especially their health and well-being,” MetService said on its website.

Using 20 years of data, meteorologists picked a threshold for 46 locations across the country, with the alert being triggered if the mercury spikes.

“We want to make sure people have all the latest information to keep themselves, friends and family safe and well,” MetService meteorologist John Law previously told 1News.