Adelaide is on track to endure a run of cold mornings not seen this early in the season since 1889. The state capital city's chilly transition into winter comes amid a string of cold and frosty mornings across South Australia this week. Clear skies, light winds and a cold air mass underneath a strong high pressure system are responsible for the run of below-average minimums. The coldest place in South Australia this morning was Yunta in the North East Pastoral District, where the mercury dropped to -4.7 degrees shortly after 7am. This was the coldest June morning in five years. Further south, Renmark was cold enough for severe frost this morning as the temperature reached -3.2 degrees. This was its coldest minimum this early in the season for 11 years. Adelaide reached a low of 2.9 degrees in the city this morning as frost crept into some of the outer suburbs. This was Adelaide's second consecutive morning below five degrees and this run could be extended to five by Sunday. If Adelaide drops below five degrees for five consecutive mornings this week as forecast, it will be the city's coldest spell this early in the season for 128 years. The last time Adelaide recorded five mornings in a row below five degrees was during August 2014. Minimum temperatures will rise at the start of next week as the stubborn frost-producing high finally gives way to a frontal system.