He said that forecast overnight lows were for air temperature, not ground temperature.
"Frosty ground is usually 3 or 4 C cooler than the overnight low, so our forecasts for -2C to -3C for a place like Queenstown until Thursday indicate 6 and 7 C of frost."
Mr McDavitt earlier said mid-winter generally lasts until the end of the month, before conditions brighten in early August.
Though more fronts are on their way - including one due around July 14 - he cannot see anything in the short term that is likely to be as severe as the weekend blast.
"That might be it for the winter."
But don't take the extra blanket off just yet, as MetService is tipping temperatures in the low single digits for most of this week.
An expected 8C in Auckland last night will seem positively balmy compared with predicted lows of 5C tonight and 4C tomorrow.
Night-time temperatures on Wednesday and Thursday aren't expected to be much better, with forecast lows of 6C and 7C, respectively.
But those predicted lows will still be higher than the 3C recorded on June 5.
Daytime temperatures will likely linger between 12C and 14C until Thursday, with little in the way of sunshine predicted for the region before Wednesday.
A lunchtime 11C in Auckland on Saturday, coupled with ice forming on city motorways, had some talking about record winter lows for the city.
Mr McDavitt said that although Saturday was Auckland's coldest day of 2008, temperatures overall were "about right" for the time of year.
While from now until the end of July is normally the coldest time, the weekend storm could be about as bad as it will get this winter, he said.
The MetService yesterday lifted snow and severe gale warnings, but the cold ensured many state highways that closed on Saturday because of snow and ice remained shut.
Most road closures were throughout the South Island and central North Island and police yesterday continued to urge caution on icy roads as far north as Waikato and Bay of Plenty.
Heavy snow remained on both the Desert Rd and National Park sides of Mt Ruapehu yesterday afternoon, blocking the main access route through the central North Island.
Cook Strait ferries resumed normal service yesterday, after a couple of crossings were cancelled or delayed because of strong winds.
MetService said no further heavy snowfalls were expected, though temperatures were low, with icy conditions likely to persist in some areas.
* A couple who were stranded in the central North Island after flying up from Christchurch weren't going to let heavy snow and road closures stop them from seeing their son.
So they did what any parents who could do would - hired a helicopter and landed on his doorstep.
Bernie and Michelle Lagan flew to Rotorua on Friday, allowing themselves a day up their sleeves to visit their 18-year-old son, Luke, who is eight weeks into a 13-week basic training stint at the Waiouru Army Base.
The two Mainlanders hired a rental car and headed for Waiouru but found themselves caught in the grip of freezing conditions which paralysed roads south of Turangi.
With families allowed only two visits during this phase of training, going home without seeing Luke wasn't an option so the couple called up an old mate and helicopter pilot, who obliged and landed them a stone's throw from Luke's barracks.
"This probably isn't something we'd do every day, but still it's great to see our son," said Mr Lagan.
