# Blue Hour The Blue Hour is a period of twilight during the day, which is characterized by a deep blue color in the sky. It is the time after sunset and before complete darkness or after complete darkness and before sunrise. This period typically lasts about 20-30 minutes and can vary depending on the location and time of year. During the blue hour, the sky can take on a range of blue hues, from soft pastels to deep, rich blues. This time is highly favored by photographers because of the unique and often ethereal quality of the light. The blue hour is especially popular for cityscape and landscape photography, as the contrast between the deep blues of the sky and the artificial light of buildings and landmarks can create stunning visual effects.