There's an awful lot to like about skiing in New Zealand. Epic terrain, empty slopes, cool locals and interesting, low-key ski areas. But there's not denying that conditions here can be tricky.
One of the most common conversations I have back in Australia is about the timing of people's ski trips here. For some reason, a lot of people end up planning their trips here in July. So let me make this really simple:
The best skiing in NZ is August and September. September typically has the most snow, but it gets pretty warm from mid September onwards, so it's hard to ski powder. August is the most reliable option for winter conditions.
Officially, the season here starts in June. Keep in mind that the club fields don't have snowmaking or grooming, so they're absolutely reliant on natural snowfall to open. Plus, rope-tows need enough snow on the tow-lines (where you get pulled up the slope) to open, so they need decent coverage to get started. Less than 50% of the last 6 seasons have opened in June. If you plan a trip here in June, there's a very good chance you'll end up sitting around in town, or skiing a strip of man-made snow down a groomer at a commercial field.