Gibbston Valley Wines chief winemaker Christopher Keys said spring, so far this year, had provided "a constant slapping", topped off on Monday with the arrival of a significant snow storm, when temperatures plummeted.
Vineyards all over the region were on standby for frost-fighting on both Monday and Tuesday nights, including having choppers in place.
Mr Keys said Central Otago viticulturists were experienced at dealing with variable conditions at this time of year, but this spring had been the "most changeable and unruly season" he had seen "in 20 years of being here".
"The good side of this is that we’re building up adequate soil moisture to ensure spring growth.
"Once we get through this, we’ll have some decent shoot growth, but it’s a bit of a constant slapping around from wind, rain, potential for frost, and snow."
Viticultura Central Otago co-owner Timbo Deaker, whose company looks after about 30 vineyards, said they were "prepped and ready to run" at the start of the week.
"We just spent the whole night [overnight on Monday] just watching the temperatures bump up and down and managed to dodge the bullet."
Overnight Monday temperatures hovered around 0.5°C, while overnight Tuesday — despite predictions of much worse — the temperature did not drop below 3°C, "which is almost like a tropical holiday in Bali, when we’re talking about frost damage".
"For the viticultural nerdy types, the thumbprint of the season is really dictated in the first eight to 10 weeks of the growing season.
"And that’s where we’re at at the moment."
All eyes would be on a November 4 super moon, because full moons could have "an incredible effect" with respect to frosts, Mr Deaker said.
But there would be some level of concern around frost damage until November 27, when traditionally frost danger had passed.
Cool soil and air temperatures had put vineyards about seven to 10 days behind schedule for now, but his "gut feeling" was once the super moon passed, the season would change and turn into a "classic" hot, dry La Nina.
"Our biggest problem from there on in will be rapid growth and chasing ... our tails, trying to keep up."
