It is the first time since 1994 Aucklanders have had their water use restricted. The restrictions include a ban on residents washing cars or watering gardens with outdoor hoses.
MetService meteorologist Aidan Pyselman said most parts of New Zealand were in for a drizzly, rainy evening, but the rain should begin clearing up in most places by Monday afternoon, leading to a dry week.
Auckland might still experience showers on Wednesday, but main centres such as Wellington, Christchurch and Dunedin should have little or no rain through the week.
Pyselman said overnight on Sunday Auckland would receive some "garden variety" rain, but it was "nothing out of the ordinary".
Wellington's weather was "looking like a fairly good sort of a week" with southerly winds forecast into the middle of the week. Highs between 12 and 15C are forecast.
"Christchurch is not going to get much at all in terms of rainfall again" aside from on Sunday night and Monday morning, and can expect highs of 13C for the week.
It's a similar story in Dunedin, though residents might notice a "little bit of drizzle" clearing by Wednesday, and highs of 12 or 13C.
Throughout New Zealand there was "nothing significant in terms of major weather features" expected over the week.
Monday's temperatures
Auckland: High 19C, low 13C
Wellington: High 15C, low 10C
Christchurch: High 13C, low 7C
Dunedin: High 12C, low 7C
Auckland's water shortage
• Stage 1 water restrictions came into force on May 16 and prohibit the residential use of outdoor hoses and water blasters unless for a health, safety, emergency or biosecurity reason.
• Under stage 1 commercial car washes are also banned unless they use recycled water; and watering of sports fields, plants or paddocks is restricted to those with an irrigation system fitted with soil moisture or rain sensors.
• Watercare further advises residents to keep showers short - four minutes or less, and only run the dishwasher or washing machine when they're full. No restrictions apply to hygiene measures, and people should continue regularly washing their hands consistent with Covid-19 messaging.