High Season (Dec−Feb)
Summertime: local holidays, busy beaches and cricket.
Prices rise 25% for big-city accommodation.
Outdoor rock concerts, film screenings and food festivals abound.
Shoulder Season (Mar−May & Sep−Nov)
Warm sun, clear skies, shorter queues.
Easter (late March or early April) is busy with Aussie families on the loose.
Autumn leaves are atmospheric in Victoria, Tasmania and South Australia.
Low Season (Jun−Aug)
Cool rainy days down south; mild days and sunny skies up north.
Low tourist numbers; attractions keep slightly shorter hours.
Head for the desert, the tropical north or the snow.
Read more: http://www.lonelyplanet.com/australia/essential-information#ixzz4CqFESeyI