Cold southerly gales were forecast to spread up the country, potentially approaching severe gales at times, before slowly easing on Monday.
Strong southerlies would persist until Wednesday, keeping maximum temperatures at 11C while overnight lows dropped to 4C, Clark said.
"Really it's Monday and Tuesday that you'll be getting those really cold temperatures because those southerlies are lingering and bringing increasingly cold air over."
Motorists travelling on the Napier-Taupo Rd were cautioned to take care as conditions could be icy - the day starting with showers and cloudy periods.
"We are expecting a little bit of sleet about the Napier-Taupo Rd early Monday morning so that's something for people to look out for as well . . . .not just showery weather but also quite cold, sleety stuff about those higher passes."
She said temperatures were expected to ease as the week progressed and southeasterlies developed while southerlies died out.
"It starts to warm up a bit as we head into the latter part of the week. That's just as those southerlies start easing off and eventually start turning northwest with light winds."
Overnight temperatures would remain well-below 10C on Wednesday and Thursday but daylight conditions would improve, Clark said.
"Those daytime temperatures are increasing because those southerlies are dying off and you get a bit more sun during the day."
Clark said it would be a bitter start to the week and encouraged locals to wrap up and stay indoors if possible.
People were advised to keep up to date with the latest forecasts in case any areas in the strong wind watch were upgraded to a full warning.
