It's spring in New Zealand and Australia at that time. A bit far I know, but I would recommend New Zealand to anyone. It has a huge range of scenery including geothermal guysers, glaciers, snow covered mountains, huge sand dunes, flat coastal plains, volcano cones, sub-tropical rainforest etc.
It also has wonderful animal and plant life (lots not found elsewhere) and an art-deco city to boot! Hiring a campervan is a wonderful way to see the country and you can basically park up for the night right next to the beach/field/lake that you happen to be by. Amazing.
We went in November and didn't get much rain. About 4 nasty days in 22. It's a bit warmer than the UK generally, and had lots more hours of sunshine.