Rain and thunderstorms swept through the Mallee last night and this morning, with some places seeing their heaviest rain in a year and a half. The region got off to a warm start to December, with temperatures over the first three days running up to eight degrees above average. On the second day of the month, it reached 40.1 degrees at Mildura and 40.9 degrees at Walpeup, the town's hottest day since January. For both places, this was the warmest first three days of the month on record. However, the extreme heat will only be short lived, as rain and thunderstorms ahead of a cool change swept over the district last night. Walpeup saw 13.8mm in the 24 hours to 9am, triple the amount of rainfall experienced for the whole of December last year, and its heaviest rain since June. Swan Hill also saw rainfall equalling half of its current December average, with 11mm recorded to 9am. Mildura picked up some of the region's most significant falls, with 24.2mm falling to 9am, the heaviest daily total in 21 months, and almost matching its entire December average. A further 10mm has fallen since 9am, now making it the town's wettest month since June. The rain will see an end to the hot weather, as the Mallee struggles to reach above the low 20's today. By tomorrow, it will struggle to even reach 20 degrees. A few showers will continue to linger in the wake of the front tomorrow. A high will begin to build over the nation later this week, bringing back the warm and dry conditions to the Mallee by this weekend.