Remember last summer? The ocean dips that were more like taking a bath, hot humid days and the great fan shortage.

It's too early to say if the sun will shine on Christmas Day but weather forecasters say it's "unlikely" this summer will break any heat records.

Forecasting scientist at Niwa Chris Brandolino said there was one thing this summer was going to make itself known for - variability.

"Last summer it was the hottest summer on record. You could have blindly picked a day in that three months and that day would have been warm.

"This summer there will be variability and each month will be its own person."

Early indications are that temperatures will be warmer than average but it is unlikely to be hotter than last summer, he said.

A combination of a marine heatwave last summer and a La Nina weather pattern created the perfect conditions for the record-breaking summer.

The average temperature was 18.8C, which was 2.1C above the 1981-2010 average, Niwa said. The previous record was 18.5C in the 1934-35 summer.

Brandolino said we could look forward to more settled and warmer weather in the run-up to Christmas, after that it would become more unsettled.

"At this stage we can't say what the weather will be doing on, say, Christmas Day or New Year's Day.

"This week has been pretty wet and it will be wet this weekend but then Thursday was beautiful and sunny - and that is a good example of how variable it can be.

"You can still have a good hour in a bad day."

The humidity felt in the past few days was set to continue for the next week.

The MetService said that the first week of summer would be anything but golden.

Showers were likely today "almost everywhere". And unsettled weather was expected throughout the week.

Meanwhile, fingers are crossed there is not another repeat of last summer's "great fan shortage".

In January and February as the mercury bubbled away New Zealand sold out of oscillating fans.

Temperatures of 30C and above were common with reports of some people paying up to $600 for a fan to combat the heat.

This year retailers are better prepared for demand.

Merchandiser for Noel Leeming Jason Bell said fans were particularly sought after last year.

"We placed a larger order this season and they're already proving popular, with a 25 per cent uplift in demand compared with this time last year."