Summer (December – February) is a great time to visit Queenstown if you plan on outdoor adventures like hiking and bike-riding. Expect warm sunny days and an abundance of outdoor activities on offer; January can be particularly busy so consider how this might impact your plans.
Spring (September – November) and Autumn (March – May) are quieter however less busy, so can be a great time to visit Queenstown especially if you'd like to catch the ski fields without the crowds in September-October. It can also be a good time to snap up exclusive lodges in Autumn and Spring.
For skiing and other snow sports, Winter and Spring (June – October) are the best time to visit Queenstown. Ski fields are generally open from mid-June to mid-October.