A cool southerly wind change which affected southern Australia last weekend has finally made an impact in the northern tropics, leading to record low temperatures. At about sunrise this morning both Borroloola and Nhulunbuy in the Northern Territory Gulf Country dipped below 20 degrees, both breaking December low temperature records. For Nhulunbuy this is the first time below 20 degrees in December since 1969, when the previous record was set. For Borroloola this is the first time in December in at least 13 years. The southerly wind change was dry enough to rid the tropical air of much of its moisture. This allowed the temperature to fall five-or-six degrees below the long-term average overnight and early this morning. The change is having a lesser effect on the western Top End where Darwin dipped to 23.9 this morning, only 1.4 below the average. But with drier air still to come for Darwin, tomorrow morning may be slightly cooler. For the Gulf Country and anywhere to the south nights and mornings will be warming up due to winds tend more northeasterly.