Southerly winds will also whip the city, turning westerly for a time and getting stronger by the evening. Strong wind gusts of up to 110km/h are expected today, especially in the middle of the day between 10am and 2pm as a band of heavy rain moves through.
It will drop to a chilly 5C overnight, with a high of 11C expected, making it one of the coldest days of the year.
It's rained every day this month since June 30, making for 14 soggy days in a row.
MetService meteorologist Angus Hines said rain or showers weren't unusual in our biggest city at this time of year.
The long-term average for wet days in June and July is 19.
But this month has started very badly. Not only has it rained every day but there have been significant totals, including 22.2mm on Thursday last week and 19.4mm on July 1.
"Accumulations are up to about 99mm and the average for the Auckland [this month] is 130mm and we're only 12 days in. So it's been pretty wet."
Over the past 31 days, it's rained on 23 days, according to MetService data.
MetService has issued a gale warning for the Manukau and Waitemata Harbours, and a southwest wind gusting to 45 knots late this morning.
Showers and the cold temperatures are expected to continue into tomorrow but will clear just in time for the weekend.
Rain is expected tomorrow morning but will disappear by the afternoon, when the winds are also expected to die out.
Saturday will be mostly fine, with a high of 13 but a bitterly cold low of 3C forecast.
Sunday will see the cloud increasing but the temperatures will also rise, a high of 14C expected with an overnight low of 8C.