Australia's south-eastern region is bracing for its hottest September day in years as a spring heatwave sweeps across the area, with temperatures forecast to soar 6C to 12C above average this weekend. The Bureau of Meteorology (BOM) predicts coastal areas will reach the high 20s, while inland regions could climb into the low to mid 30s.
What's Causing the Unseasonable Warmth?
According to BOM senior meteorologist Dean Narramore, a combination of a cold front in Western Australia and a high-pressure system in the Tasman Sea is dragging warm, dry, and sunny weather towards south-eastern Australia. "We're going to see cooler conditions Monday and Tuesday, but then we could see an even bigger burst of heat probably late next week and into next weekend for much of the same part of the country," Narramore told Guardian Australia.
Which Cities Will Feel the Heat?
Several major cities are set to break temperature records this weekend. Canberra and Melbourne are expected to record their highest September temperatures since 2023, with Melbourne forecast to reach 27C on Sunday. Sydney is predicted to hit 28C, while Hobart is set to experience its hottest September day in seven years, reaching 27C before temperatures nearly halve by Monday.
| City | Forecast Temperature (Sunday) | Record Note |
|---|---|---|
| Melbourne | 27C | Highest since 2023 |
| Sydney | 28C | Well above September average |
| Canberra | ~25C | Highest since 2023 |
| Hobart | 27C | Hottest September day in 7 years |
The 'Spring Rollercoaster' Explained
Narramore describes these fluctuations as a classic "spring rollercoaster" — a common phenomenon at this time of year. "We're going to see cooler conditions Monday and Tuesday, but then we could see an even bigger burst of heat probably late next week and into next weekend," he said. This pattern of rapid heating and cooling is typical for spring, as the atmosphere transitions from winter to summer.
Key Takeaways
- Hottest September day in years forecast for south-eastern Australia this weekend.
- Temperatures will be 6C to 12C above average, with coastal areas in the high 20s and inland in the low to mid 30s.
- Melbourne, Sydney, Canberra, and Hobart are all set to break or approach records.
- A cool change will arrive Monday, but another heat burst is likely late next week.
- The "spring rollercoaster" pattern means wild temperature swings are normal.
What to Expect in the Coming Weeks
After the weekend heat, a cool change will move through on Monday and Tuesday, dropping temperatures significantly. However, Narramore warns that another, potentially even hotter, burst of heat could arrive late next week and into the following weekend. This on-again, off-again pattern is expected to continue through September.
FAQ
Which Australian cities will experience the hottest September day?
Melbourne, Sydney, Canberra, and Hobart are all forecast to see their hottest September day in years. Hobart is expecting its warmest September day in seven years.
How hot will it get during the September heatwave?
Temperatures are expected to be 6C to 12C above average. Coastal areas will reach the high 20s, while inland regions could hit the low to mid 30s.
What is the 'spring rollercoaster'?
The 'spring rollercoaster' refers to the rapid fluctuations in temperature common during spring, as the weather transitions from winter to summer. It often brings bursts of heat followed by cool changes.