Parts of Australia's southeast just shivered through their coldest June morning in at least 20 years.   

Dry air on the western flank of the low over the Tasman Sea producing frosty nights across south east Australia. pic.twitter.com/OfKGEP5TVB

— Andrew Miskelly (@andrewmiskelly) June 18, 2024

A Tasman Low has directed icy southerly winds over eastern Australia for several days and a high-pressure system has moved in behind it causing temperatures to plummet overnight with clear skies. 

The images below show the low in the Tasman and mostly clear skies over the southeast, with some lingering fog on the ranges on Wednesday morning.

Image: Himawari-9 satellite image for the three hours leading up to 9:20am on Wednesday, June 19. 

This set-up caused the coldest morning in decades in the southeast: 

Tasmania 

• Smithton recorded its lowest temperature in records dating back to 1962, with a minimum temperature of –4.5°C. 
• King Island saw the coldest temperature since July 2020, with a minimum of –0.1°C 

Victoria 

• Westmere’s overnight temperature dropped to –5.7°C, the coldest morning in records dating back to 2006 
• Sheoks observed the coldest June morning in 29 years, with a minimum of –2C. 
• Omeo, saw its coldest June morning since 1995, with the temperature dropping to –6.4°C 
• Melbourne recorded its coldest morning in nearly two years, with a minimum of 1.4°C 
• Melbourne airport recorded the equal coldest June morning since 1996, with a minimum of 0.2°C 
• Mortlake racecourse’s temperature plummeted to –3.5°C, the coldest June morning in 28 years and in any month for nearly 18 years 
• Bendigo’s minimum temperature plummeted to –3.9°C, the coldest morning since August 2013 

New South Wales 

• Griffith airport’s temperature dropped to –4°C, the coldest morning since August 2018 
• Sydney Observatory Hill’s minimum was 6.5°C, the coldest morning in a year. 

The wind chill across the southeast has made these temperatures feel 4 to 6 degrees colder than the actual temperature.  

While the temperature at Sydney Observatory Hill was 6.5°C at 7:30am Wednesday, June 19, the apparent temperature was 1°C due to this wind chill.  

At the same time in Melbourne, the apparent temperature was –2.3°C, with the actual sitting at 1.4°C.  

The cold start to the morning will mean that Wednesday’s daytime temperatures will struggle to reach above 16 °C in Sydney, Hobart and Melbourne.  

Unfortunately, this means that Thursday morning will be another cold one for the southeast, before the east is reprieved on Friday ahead of a cold front. However, the southern capitals’ minimums will remain cold through the weekend into next week.