Short version:
- Southern coast (Sydney, Melbourne, Adelaide, Perth, Tas): summer (Dec–Feb) for beaches, shoulder (Sep–Nov, Mar–May) for everything else
- Centre (Uluṟu, Alice): April–October
- North (Cairns, Top End, Kimberley): May–October
Full-country trip sweet spot: May–September. Dry in the north, mild in the south.
Australian seasons
- Summer: Dec, Jan, Feb
- Autumn: Mar, Apr, May
- Winter: Jun, Jul, Aug
- Spring: Sep, Oct, Nov
Christmas = summer peak. National school hols: mid-Dec to late Jan.
By region
Sydney / NSW coast
- Summer 25–30°C, busy beaches • Autumn the best weather • Winter 12–20°C, sunny but cold ocean • Vivid light festival May/Jun
Brisbane / SE QLD
- Subtropical. Winter (Jun–Aug) is the best time: 12–22°C, dry • Summer humid + storms • Stinger-free ocean year-round
Melbourne / southern VIC
- “Four seasons in one day” all year • Summer hot then cool changes • Winter 7–14°C, grey, food/gallery weather • GOR anytime; whales Jun–Oct
Adelaide / SA
- Summer 30°C+, heatwaves 40°C+ • Winter 8–15°C, moody wine country • Spring/autumn best for wine
Perth / SW WA
- Mediterranean. Summer 30°C, beach perfect. Fremantle Doctor (afternoon sea breeze) • Winter 18°C days. Wildflowers Aug–Oct
Nullarbor
- Spring/autumn ideal • Summer roasting • Whale-watching May–Oct at Head of Bight
Uluṟu / Red Centre
- April–Sep: the only realistic window. May–Aug: cool nights, warm days, hikes possible
- Oct–Mar: 40°C+, walks shut by mid-morning
Top End (Darwin, Kakadu)
- Dry May–Oct: go now
- Build-Up (Oct–Dec): hot, humid, oppressive
- Wet (Dec–Apr): monsoon. Kakadu mostly closed but waterfalls roar
Kimberley
- Dry May–Oct: only road-trip window
- Wet Nov–Apr: Gibb closed
- June–August peak — book ahead
Cairns / Tropical QLD
- Dry May–Oct: low humidity, no stingers, clear reef
- Wet Nov–Apr: hot, humid, box jellies, possible cyclones
Tasmania
- Summer (Nov–Apr) 15–25°C, ideal hiking
- Winter cold, snow on mountains, Dark Mofo
- Always pack layers
Full-country window
May–Sep is the sweet spot. June–August best for the outback. Avoid Dec–Feb for north + outback.
Events worth timing around (or avoiding)
- Australian Open — January, Melbourne
- Sydney Festival — January
- Adelaide Festival / Fringe — late Feb/March
- Vivid Sydney — late May/early June
- Dark Mofo — mid-June, Hobart
- Garma — late July/early Aug, Arnhem Land
- AFL Grand Final — late Sep, Melbourne
- Melbourne Cup — first Tuesday in November
- Christmas/NYE — Sydney Harbour fireworks