"It won't be cold though, with [a high of] 21C."
The front could also cause headaches for cricket fans heading to the Bay Oval for the Black Caps Twenty20 international against the West Indies from 2pm - rain is expected in Tauranga this morning before clearing during the afternoon.
The north's wet weather is coming from the top of the South Island, where a heavy rain watch is in place for Buller and Westland, north of Greymouth, in the hours before 7am, Farmer said.
The east and southern part of the South Island escape rain and showers, but the front will move over the North Island - the lower half in the morning and the upper half in the afternoon before clearing late afternoon or early evening, she said.
"Basically you get rain and then clearance behind that. That's the normal thing for these fronts."
Respite will be brief.
A "nasty" low moving across the country will bring rain for most and strong winds for some tomorrow, Farmer said.
Conditions could again be ropey for the cricket, with wet weather again possible for the second Twenty20 in Tauranga, with the first ball between the Black Caps and West Indies due to be bowled at 7pm.
Southerners look likely to fare better tomorrow, Farmer said.
"It does look like the South Island might get off fairly well. Bit of rain but probably not as much."
The North Island would be mostly wet and, in places, windy, especially in Northland, Auckland and Taranaki.
"It's not enough to warrant warnings, but it is going to be gusty."
Again, the wet and windy turn will be brief, with showers gradually clearing everywhere across the North Island on Tuesday.
"The low, it'll be travelling quickly to the east."