Group 1 - The weather in Heilongjiang Province will experience significant fluctuations, with temperatures rising and then falling, resembling a "roller coaster" effect, along with two minor snowfall events [1][3] - From December 27 to 28, temperatures in most areas of Heilongjiang will rise significantly, reaching highs between -8°C to -4°C, with specific locations like Daqing, Harbin, and Mudanjiang seeing highs between -2°C to 0°C [3] - Starting December 29, temperatures will continuously drop, with lows in certain northern areas reaching between -36°C to -32°C, while other regions will see lows between -28°C to -24°C [3] Group 2 - There will be two snowfall events in the upcoming week, with light snow expected on December 28 in various regions, and localized moderate snow in northern areas [3] - The weather conditions, including fluctuating temperatures and snowfall, may lead to slippery roads and reduced visibility, impacting transportation [4] - Outdoor activity participants are advised to take precautions against cold weather and potential health issues, as well as to prepare for road conditions due to snow and ice [4]