The next full Moon will rise on September 26, 2026, at 18:49 Paris time. This date offers an excellent chance to see a lunar halo, a glowing ring that sometimes surrounds the Moon. This natural phenomenon happens when light from the Moon passes through ice crystals in high-altitude clouds called cirrostratus, which sit between 6,000 and 13,000 meters above Earth. These clouds are usually thin and hard to spot, except when they appear in a slightly misty form known as nebulous, which can make the halo around the Moon more visible. A lunar halo is not a mystical event but a scientific occurrence. It differs from a rainbow, which forms when light bends through liquid water droplets, not ice crystals. The appearance of a lunar halo can suggest that a warm weather front is approaching, which might bring rain within the next day. However, if the halo looks broken or fragmented, it usually means the weather change will be mild and not cause significant effects. While observing a lunar halo can give a quick clue about upcoming weather, it should not be used as a substitute for a full weather forecast. The cirrostratus clouds that create the halo do not produce rain themselves, but they often signal that a weather change is on the way. In winter, seeing a halo in the evening can be an early sign of a more humid day the following morning. This natural phenomenon highlights the connection between the sky and the weather, offering a simple way for people to observe atmospheric changes. Though not a precise tool for weather prediction, a lunar halo can be a fascinating and accessible way to engage with the natural world and understand the delicate balance of Earth's atmosphere.