Winter was knocking on the door in New South Wales and southern Queensland this morning as some areas shivered through their coldest May start on record. Clear skies and light winds in the wake of a cold front allowed temperatures to plummet in eastern Australia, with some areas seeing their first frost of the season. Queensland registered its first sub-zero temperature of 2017 as the mercury dipped to minus 0.4 degrees at Applethorpe, in the Southern Downs region. Oakey's 1.3 degrees was also the lowest of the year and six below average for May. Large swathes of New South Wales and the ACT were also covered in frost as the sun rose. Dubbo shivered through its coldest May morning in 96 years of records, dropping to minus four degrees just after 6:30am. Canberra's low of minus 4.5 degrees was the coldest morning in 10 months. Even parts of Sydney were crunchy underfoot at first light, including Richmond (-0.4C) and Campbelltown (0C). The city had its coldest May morning in 18 years, with a minimum of 7.1 degrees at Observatory Hill. This morning's cold start was one in a string of frosty mornings that will ensure a fitting transition into winter across much of eastern and southern Australia this week.