First Day of Summer Delivers Record Heat in the West — Record Cold in the East

As Australia flipped its calendar to the official start of summer on 1 December 2025, the weather delivered something few expected: scorching heat in the west — setting new records — while the east shivered through unseasonal chill.

Blistering heat scorches Western Australia

• In Perth, temperatures soared to 39 °C, the hottest December 1 start to summer on record — exceeding the previous high of 37.4 °C set in 1979.
• Coastal and regional areas also baked under the heat: Geraldton reached 42.2 °C, the highest for that city’s first summer day in nearly a century.
• Even typically cooler coastal zones felt the furnace: Albany Airport registered 36.2 °C — its highest December 1 in over seven decades.

Across the west and south-west, temperatures ranged 8–10 °C above seasonal averages, defeating any expectations of a mild seasonal shift.

The extreme heat has triggered serious fire risks: emergency services reported at least one home destroyed and warned of exposed communities amid hot, dry, windy conditions.

Meanwhile, the east braces for an icy summer start

In stark contrast, cities in south-eastern Australia plunged into an unexpected cold snap:

• Melbourne endured its coldest first day of summer in nearly 30 years, with a high of just 15 °C — far below the usual December norm.
• Snow even dusted alpine regions as cold southerly winds and rain swept through parts of Victoria and Tasmania, a rare sight on the dawn of summer.
• In addition to Melbourne, other southeastern areas such as Canberra and Hobart experienced similar unseasonal chills as a cold Southern Ocean air mass moved inland.

For many residents expecting summer warmth, the cold came as a shock — and a reminder that Australia’s climate extremes can span more than just heat.

Consequences — heat hazards, cold shock and weather whiplash

• Fire danger on alert: In Western Australia, the extreme heat, dryness and winds have elevated bushfire risk. Authorities warned residents to stay alert, especially in vulnerable coastal and forested zones.
• Public discomfort and disruption: While western households scrambled for shade and air-conditioning, people in the east dug out jackets and heaters — many describing their summer’s first day as more like mid-winter.
• Weather whiplash and planning chaos: The sharp divide — heat one side, cold the other — complicates agriculture, holiday plans and emergency service readiness. Some regions face fire bans; others risk flooding or icy alpine conditions.

Why the stark contrast — and what it reveals

Meteorologists attribute the split to a rare configuration of air masses: a hot interior trough pushing warm air westward, while a cold Southern Ocean system dragged chilly air into the southeast.

The event underscores how Australia’s weather — influenced by global climate patterns and regional pressure systems — can swing dramatically from one extreme to another, even on the same date.

Looking ahead — brace for a volatile summer

Weather forecasters warn that this could be a preview of what’s to come: hot, fire-prone conditions in the west and unpredictable, possibly cold snaps in the southeast.

For now:

• Residents in WA have been urged to remain vigilant, prepare for fire risk, and avoid outdoor work during peak heat hours.
• Southeast communities should stay weather-aware, especially alpine and coastal areas prone to sudden cold or storm — and plan accordingly.

Australia’s first day of summer didn’t deliver a unifying taste of sun — but a vivid reminder of the country’s climate extremes. Whether in heat or cold, this unexpected debut signals a season that will demand flexibility, alertness and community resilience.