It may technically still be Autumn, but the 'Solar Winter' is now underway in New Zealand.

The Solar Winter, which began on May 11, is the quarter of the year (three months) with the least amount of available sunlight.

"In other words, our shortest days and longest nights of the year are now with us until early August. Some people love this time of year, others miss the long, brighter, days of summer," says a spokesperson for WeatherWatch.co.nz

"The coldest air for NZ usually peaks in July, August and sometimes September (especially further south)."

Solar Winter is measured six weeks either side of the Winter Solstice, or 'shortest day' of the year, which this year is on June 21 (at precisely 9.13pm).

WeatherWatch.co.nz says the specific date/time of the shortest day moves around a little every year, but is usually around June 21/22.