Climate scientists are expecting one of the warmest Junes on the record books, with temperatures so far tracking well above average.
"It's certainly been one of the most anxious lead-ups in the years I've been here," Mt Ruapehu customer relations manager Annah Dowsett said yesterday.
"But then we did have that also in 2008, and then it dumped down."
A cold blast gave both sides of the mountain a blast last night, but the snowy weather was forecast to clear again this weekend.
Ms Dowsett said staff were reviewing conditions daily and the season could open at relatively short notice, especially if the weather allowed staff to ramp up snowmaking.
"We'll move heaven and earth - if it means that we are working 24 hours around the clock to get it operational, we'll certainly be doing that," she said.
"People are disappointed there is no snow - they know we can't do anything about it, but they are ready to just come to the region this weekend anyway."
In Ohakune, the season delay did not mean fewer visitors this weekend.
The annual Mardi Gras is expected to draw 7000 visitors - 2000 more than last year - to the small mountainside town, organiser David Williams said.
"My understanding is town is close to full up, if it's not already full."
In the south, those areas that had been able to open - Mt Hutt and Coronet Peak - were attracting "reasonable" numbers of visitors, NZSki sales and marketing general manager Craig Douglas said.
"But it's still very early in the season, and we are certainly far from capacity."
While June had been warmer than expected, healthy amounts of snow usually arrived in time for the annual July school holiday boom.
"We've had better, but we've had worse. In this industry we deal with the vagaries of weather ... and they are very vague."
National Institute of Water and Atmospheric Research meteorologist Chris Brandolino said NZ's average temperature across the month had so far been 10.5 deg - 2 degrees above the long-term average for June.
Anything more than half a degree over the average is considered above normal, but a 2-degree difference was "well above normal", he said.
Whenuapai in Auckland recorded a mean of 12.8 deg - 1.6 deg above average - and was on track to have its warmest June since records began in 1945. Tauranga, which has enjoyed a mean of 13.1 deg was due to get its warmest June in a century, while Mangere in Auckland, with a 13.7 deg mean that was 1.9 deg above average, would likely get its second warmest.
Mr Brandolino said the warm start to the winter was largely due to a lack of southerlies.
Auckland climate scientist Dr Jim Salinger calculated that June was tracking as the equal warmest with 2003, while Auckland may record its fifth warmest June.
"There is no cold weather on the books until July 1, when a brief southerly will swoop up the South Island - so it will most likely hold its place."
Dr Salinger said winters in New Zealand were becoming consistently warmer - last year's was the warmest on record - a trend that would become more apparent as the globe warmed.
