Skywatchers across Northland have a chance to see a supermoon tonight, a phenomenon now shining over the region that won't be visible again until 2034.

While a rain band was expected this evening, Northlanders would have a window of clear sky to see the supermoon from about 10pm. The sight occurs when the moon is within 90 per cent of its closest position to Earth. The supermoon has not occurred since 1948.

Whangarei amateur nature and wildlife photographer Ross Armstrong spotted the supermoon on Sunday evening . He made it his mission to get under the shadow of Mt Parihaka to capture a photo.

"I drove up Hatea Drive at around 7.30pm and wanted to line up the moon and the monument. Just as I did so, a hawk flew into the shot. It was perfect," he said.

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This morning, the centre of the moon was about 356,510km from the centre of Earth. That's about the distance of nine times the circumference of the earth.

According to Peter Felhofer, director at Planetarium North in Whangarei, the moon and Earth could be compared to a hula hoop dance.

"Earth is like a hula hoop dancer and the moon's orbit, the hula hoop. The moon is always doing this elliptic orbit, but never this close.

Two things must happen for a supermoon to come close - perigee and syzygy. The moon must be within 90 per cent of its closest position to Earth - called perigee. The Earth, sun and moon must also line up as the moon orbits our planet. This straight-line configuration of three celestial bodies in a gravitational system is called syzygy.

Mr Felhofer said the moon was closest to Earth at 2.56am this morning but would still be spectacular tonight.

The Maunu observatory will open from 7.30pm today, with the team offering a "tour of the sky".

MetService meteorologist Georgina Griffiths told the Northern Advocate that an incoming rain band would clear at about 10pm tonight. The next supermoon will be in November 2034.