Heh, at least you will experience NZ in the worst possible season. - Mid winter to early spring. After that trip you can be sure that the rest of the year must be better :)

In past years at that time in christchurch people complained about their pipes freezing, last winter it snowed in the city, and theoretically you get the worst of the winter rain. (I say theoretically as we have had a miserably wet summer so far).

Really if you like it here then you will LOVE it for the rest of the year. Bring some very warm clothes....