In Hastings, the temperature by 9am was 2C and in Wairoa it was 3C but felt like 0C.
The weather was fine and became warmer throughout the day with a high of 17C in Napier, 16C in Hastings, 15C in Waipukurau and 16C in Wairoa.
Daytime temperatures are expected to remain in the upper teens throughout the week but nights will be cold until Monday.
The cold is caused by a ridge of high pressure over the country meaning no cloud and wind, alongside longer nights and shorter days.
More frosty mornings can be expected today and tomorrow .
As a low-pressure system moves across the North Island towards the end of the weekend and on Monday, overnight temperatures will warm to 10-11C but daytime temperatures will remain the same, James said.
There is also some rain expected on Monday, but it will "not be a drought breaker".