A blue moon looks essentially the same as any other full moon in the night sky—it does not appear blue in color under normal conditions

. The term "blue moon" actually refers to a rare calendar event, such as the second full moon in a single calendar month or the third full moon in a season that has four full moons, rather than the moon's color

. The moon can appear blue only in very rare atmospheric conditions, when particles in the air—such as ash or dust from volcanic eruptions or large wildfires—are of a specific size (about one micron wide). These particles scatter red light and allow blue light to pass through, giving the moon a bluish tint

. One historic example was after the 1883 eruption of Krakatoa, when the moon appeared bluish for several years due to volcanic ash in the atmosphere

. In summary:

• A typical blue moon looks like a normal full moon—white, yellow, or sometimes orange or red due to atmospheric effects, but not blue

• A truly blue-colored moon is extremely rare and happens only when atmospheric conditions include specific-sized particles that scatter red light

• Most "blue moons" people refer to are calendar-based events, not color changes

Therefore, unless there is an unusual atmospheric event, a blue moon does not look blue but just like any other full moon.