Sunsets like these at the Five Mile Bay lookout on Lake Taupo will get later as daylight hours get longer. Photo / John Campbell

The longest days of summer are on their way as sunrises get earlier and sunsets stretch out into the evening.

According to Weather Watch head forecaster Philip Duncan, Kiwis will be able to get the most out of their summer days from December 22, the official longest day of the year.

Known as the Summer Solstice, the exact opposite to winter's shortest day of the year, the longest day of the year will spread the most daylight of the summer for one day across the country - from almost 15 hours in Auckland to almost 16 hours in Invercargill.

The latest sunsets begin at the end of December and run into the first week of January according to Duncan.

He said the sun's earliest rises in New Zealand are now, in the first and second weeks of December.

"Planet Earth is not perfectly round. In fact it was Isaac Newton who first correctly suggested that Earth was a sphere that is squashed at its poles and bulges out at the equator.

"It's this shape, along with Earth's tilt, that helps give us all the varying sunrise and sunset times across New Zealand - and you may be surprised to know that in fact it's around now that we have our earliest possible sunrises but nearly a month out from the latest sunsets."

On the longest day of the year, on December 22, the sun will rise at 5.28am.

And if the unusually early heatwave continues, Kiwis will have plenty of time to enjoy all the treats of outdoor summer living.

Temperatures have soared in the past 10 days to 29 degrees in places like Masterton and Blenheim, with larger centres such as Hamilton, Queenstown and Taupo hitting 27.

The high is expected to continue in many parts of the country this weekend.

Sunrises and Sunsets

Auckland
• Earliest Sunrise - Past few days/today at 5:54am
• Latest Sunset - First week of January at 8:43pm
• Solstice: 5:58am to 8:40pm (14 hours, 42 minutes of available sunlight)

Wellington
• Earliest Sunrise: Today and next week at 5:41am
• Latest Sunset: First week of January at 8:57pm
• Solstice: 5:44am to 8:54am (15 hours, 10 mins of available sunlight)

Invercargill
• Earliest Sunrise: Next few days at 5:47am
• Latest Sunset: Last week of December, first week of January at 9:41pm
• Solstice: 5:50am to 9:39pm (15 hours, 49 mins of available sunlight)