Trip to New Plymouth, NZ

[Mendana]

i am planning a trip from Melbourne to New Plymouth(1,400 miles), probably single handed.
I am keen to get advice on weather services for the purpose of planning the best time of year and ongoing daily weather advice prior and during the trip.
I don't particularly want to hire a weather person, due to the expense, which appears to be about 50 euros per day for two detailed daily emails....some help please..