A cold spell is hitting parts of the US with heavy snow and travel problems. Last weekend, Wisconsin saw 20-30cm of snow, with some areas reaching 35cm. Early this week, a storm over Wyoming and Colorado dropped continuous snow until Thursday morning. Central Colorado and northern New Mexico were hit hard, with up to 30cm of snow. Denver had its first heavy snowfall of winter, causing nearly 1,000 flight delays or cancellations on Wednesday and Thursday. Northern Colorado also faced dense fog on Thursday, reducing visibility to 100-200 meters. The National Weather Service warned about this dense fog. Snowfall has eased now, but another storm is expected this weekend in the Rocky Mountains. The new storm will bring heavy snow, strong winds, drifting snow, and blizzard conditions. The US will see abnormally cold weather in central and northern regions through early winter. Meanwhile, Australia is starting its summer with unusual weather contrasts. The south-east mountains had freezing temperatures and snow, while the west endured a heatwave with temperatures soaring above 40°C. Temperatures in central Australia may hit the mid-40s by weekend. The heatwave is set to spread across Australia next week, affecting residents and tourists, especially the vulnerable. The Australian Bureau of Meteorology issued a fire weather warning for southern New South Wales on Friday due to rising wildfire risks. People are advised to stay indoors and keep air conditioning running as dangerous conditions continue next week.