Southeastern Australia has been sweltering for well over a week, with the strongest pulse of heat just before the end. South Australia The heat pushed into South Australia almost two weeks ago beginning an eleven day run of over 30 degree temperatures. This is the third longest run of March heat in over 120 years of records. Mt Gambier smashed the March record for consecutive days above 30 degrees with eleven. This is five more than the record and is also equal to the summer record set in 1956. Victoria Melbourne has broken multiple records in this run of heat despite having records dating back 156 years. It has had the longest ever run of days above 30 and 32 degrees with nine days reaching 32.7 and above. The previous records were eight days above 30 and seven above 32, set in the same run in February 1961. Nights have also been very warm in Melbourne meaning that buildings without air conditioning have struggled to cool from the daytime heat. The city has equaled the record of six mornings in a row failing to drop below 20 degrees. Tonight is likely to break the record with the mercury likely to be in the low 30's or high 20's most of the night. There is a chance that tonight will break the record for the warmest March minimum of 26.3 degrees. All of Victoria has been bombarded by this heat with temperatures rising as high as 40 degrees at Cape Nelson. This is 19 degrees above the March average and half a degree short of the March record. Tasmania Records have been equaled and they have been doubled in Australia's southern most state. Launceston has been staggering in its consistently hot temperatures. It has doubled its record run of four days above 30 degrees with a staggering eight days, including a new record March temperature of 33 degrees. Hobart came very close to its longstanding March record of 37.3 degrees today, reaching a top of 36.7 degrees. Just inland of Hobart, Bushy Park succeeded in equaling its 47 year old March record of 37.6 degrees. Strathgorden and Strathan had their hottest March day in at least 30 years. Cool change The heat has built across SA, VIC and TAS due to a blocking high to the southeast which has simultaneously fed heat from central Australia into the southeast, whilst blocking cold fronts from reaching the mainland. This high will finally get pushed further east by a cold front delivering cool air. This front has already brought a welcome cool and gusty change to parts of South Australia, dropping temperatures suddenly. Ceduna fell 8 degrees in 10 minutes this afternoon, with a similar drop in store for Adelaide after dinner. Victoria and Tasmania will have to wait a while longer for the change to arrive with temperatures not expected to drop until morning. Some locations in eastern and northern Victoria are likely to break their March records for the warmest night. The change is likely to reach Melbourne near the end of peak hour.