The northeasterly airflow and humid warm weather we have had for a while ends today as the airflow changes to the southwest. Most regions will have rain or showers today as various troughs and fronts move through.

Northland, Auckland, Waikato & Bay Of Plenty
Showers. Northerlies change strong west to southwest this morning. Late evening or overnight showers becoming heavy, perhaps some hail and thunder Auckland southwards.
Highs: 16-20

Western North Island (including Central North Island)
Showers turn to rain this morning as northerlies change strong westerly, gales about coastal areas. From late afternoon there could be thunderstorms with hail. Snow about higher parts of the Desert Road at night (800m and higher).
Highs: 13-17

Eastern North Island
Mostly sunny, early showers clear Gisborne. From afternoon rain or showers spreads from the west as northerlies tend gusty west to northwest. Gisborne may continue to stay dry for the rest of the day.
Highs: 18-22

Wellington
Showers turn to rain late morning as strong northerlies change westerly, rain eases to showers in the afternoon with sun breaking through at times. Late afternoon and evening there is a chance one or two showers may be heavy with hail and thunder.
Highs: 16-17

Marlborough & Nelson
Rain, clearing in the afternoon with sun breaking through as northerlies change gusty westerly. Southern Marlborough and the northwest Nelson ranges continue to see showers or rain.
Highs: 15-17

Canterbury
Rain pushes northwards during the morning with a southwest change, strong about the coast. There is a risk of hail and thunder late afternoon and evening before easing. Overnight rain becomes widespread as southwesterlies strengthen with gales developing about the coast. Overnight snow lowers to 500 or maybe 400m.
Highs: 12-16

West Coast
Showers, heavy rain north of Greymouth eases around midday. From afternoon showers may be heavy with thunderstorms and hail, in the evening starting to dry up for South Westland as southwesterlies tend to the south.
Highs: 10-14

Southland & Otago
Morning rain eases to showers, south to southwesterly winds strengthen from afternoon with rain moving back in, there may be hail and thunder as these winds strengthen, gales about coastal areas by evening. Snow to 800m lowers to 300m overnight.
Highs: 8-11