Matariki: Will the weather clear in time for stargazing?

The forecast for stargazing this Matariki long weekend is looking promising with the heavy rain battering Aotearoa expected to ease on Friday.

But if you are planning to wake up early to view the cluster of Matariki or the star Puanga, it might pay to wear several layers, especially in the South Island.

MetService meteorologist Alwyn Bakker told RNZ it was generally good news.

"We're going into a ridge, which for astronomers, that's pretty exciting because that tends to mean less cloud cover and more settled weather. It unfortunately means it's also going to be really cold.

"So wrap up really warm when you go out to look at Matariki, we've got a few places that are going to be going down to minus five-ish in the South Island."

Twizel has a forecast low of -8°C on Saturday morning.

Bakker said the heavy rain that had hit across Aotearoa this week should clear out by Friday.

"It'll still be wet on the ground and that'll help contribute to a lot of frosts, but there should be considerably less falling from the sky."

Bakker is picking Westport as the best place to view the stars, partly because it should have clear skies and partly because it will be comparatively warmer to the rest of the South Island.

"But generally the West Coast of the South Island will be pretty good through most of the weekend. Getting on to Saturday and Sunday, it will improve for the upper half of the North Island.

"In coastal regions, it'll be a bit more patchy cloud wise. But in general, there should be a good chance for everybody to see Matariki or Puanga over the weekend."

The weather is expected to improve as the weekend goes on, so Sunday morning will probably have the best conditions for stargazing in many places, he said.

"The place that will be most tricky, I guess, is going to be around the east coast of the North Island around Gisborne. There looks to be a bit more chance for cloud cover there. So crossing fingers, everybody will get their chance, but later in the weekend will be better for them."

The upper half of the North Island should be clear Saturday and Sunday mornings. The west coast of the North Island is generally clear as well and the weather on the east coast is improving Sunday into Monday, he said.

Sunday morning was also looking good for the east coast of the South Island, including Christchurch and Dunedin. Southland will be patchy on Saturday, then getting better into Sunday, he said.

Auckland will host the national hautapu ceremony on Friday morning at Takaparawhau, Bastion Point.

"So Friday, it should be decent for Auckland. It will be better on the Saturday, but there should be a good opportunity to see Matariki on the Friday as well," Bakker said.

To find the Matariki cluster, look low on the eastern horizon before the sun rises and find three bright stars in a line - this is Orion's belt or Tautoru.

Next trace a line to the left of Tautoru until you come to the bright orange star Taumata-kuku (Alderbaran) - part of a group of stars in the shape of a pyramid, which are themselves part of the constellation of Taurus. From there, continue to the left until you find a small cluster of stars. That is Matariki.

Cloud cover

MetService have also launched an interactive cloud cover map to help people work out when is the best time to see Matariki in their area.

Bakker said the map will show the current time as satellite imagery, but at a certain point it will change over to modelling data.

"So that is based on essentially where the computer thinks there's going to be cloud cover, where the models think there's going to be cloud cover. We pick which of the various models it's showing on the website so we can fine tune it to make sure it's going to be as accurate as possible.

"Cloud is a bit finicky, so it won't be perfect, but it's a heck of a lot better than guessing."

You can also click on different areas and it will show you a percentage of cloud cover, indicating how patchy the cloud is going to be, so if it is 100 percent you probably will not see very much, but if it is less than 50 percent there will be patches of cloud and you should be able to catch a glimpse of the stars, he said.