Saturday is looking like the wettest day of the weekend, however, Sunday will see temperatures plummet around the country.

While forecasters say it's still too early to confirm exactly where Cyclone Oma - this afternoon downgraded to a category 2 - will hit but either way New Zealand will be on the receiving end of some heavy rain and strong winds.

Showers have already hit Northland today and MetService duty forecaster Tui McInnes said Auckland will also likely see a few today and tomorrow.

However, the majority of the rain will hit on Friday.

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As for Cyclone Oma, McInnes said it was still early to definitively say exactly where it will hit but it was currently tracking towards the top of the Coral Sea on the Queensland coast.

"The latest models have placed the most likely scenario now lingering around the Coral Sea. That said, there are still some that bring some tracks towards us and it can't be ruled out.

"From tomorrow the clearer picture starts to develop because we're still waiting for the cyclone to gain a bit of motion because it's still quite slow."

The Fiji Meteorological Society this afternoon re-categorised it as a category 2 cyclone, down from a 3 overnight.

But whether it hits New Zealand or not, Kiwis are still in for wet and wild weekend.

"Notwithstanding the evolution of the tropical cyclone, we are looking at severe weather this weekend. Regardless it's set to be a wet and windy weekend because there's quite warm tropical air moving over us and at the same time there's a big amount of cold and more polar air tracking up New Zealand and they will meet."

The interaction of the two fronts will be "quite volatile" and creates the perfect storm for a low pressure system to develop and bring the rain and wind.

As for where the rain will hit, it's still a bit early to be precise, but at this stage McInnes said most of the country can expect some rain with the South Island bearing the brunt of it.

"At the moment the North Island looks to get quite a good persistent amount of rain on the Saturday and as we go into Sunday it looks like eastern regions on both islands ... are the more exposed places and getting strong winds."

McInnes said Saturday is likely the wetter day, while Sunday will feature stronger winds and colder temperatures.

"Temperatures are actually set to get quite cold. For example, a classic one is Christchurch. Their forecast max for tomorrow is 30 degrees. Their forecast on maximum on Sunday is 14. That's quite a drop.

"There's a few places in the North Island where the forecast max on Sunday and Monday is closest to the forecast minimum for tonight and tomorrow night. Hamilton is one. The forecast min tonight and tomorrow night is 17 degrees ... the forecast maximum on Sunday is 19 degrees."

The news is likely unwelcome for those attending 20th anniversary celebrations of Splore at Tapapakanga Regional Park which runs from Friday night to Sunday.

However, a spokeswoman for Splore said the event will be held "rain or shine".

"Some of our best Splore festivals have been in the rain. It's about the attitude people bring – along with appropriate clothing to stay warm and dry."

She said Splore management team were constantly monitoring the weather and were in touch with weather experts to monitor the situation and "ensure the audience will be safe."

"Safety is our number one priority when considering the weather and our next priority is getting people into the festival as rain can slow this process down. We ask people to try and get to Splore and be set up before any significant rain is scheduled."

Six60 is also holding their massive sold-out gig at Western Springs which is expected to see around 50,000 pour through the gates.

On Sunday the winds change from north to northwesterly to south, southwesterly being the cause for the cooler temperatures which will continue into Monday.