noctilucent

/ˌnɑktɪˈlusənt/
adjective
  1. Describing clouds that shine at night, especially very high clouds that reflect sunlight after sunset.
    • Scientists study noctilucent clouds to learn about the upper atmosphere.
    • We stayed up late hoping to see the rare noctilucent clouds after the sun went down.
    • Noctilucent clouds appear as glowing silver-blue streaks in the summer night sky.
Antonyms
What does "noctilucent" mean? | whatsthatwordmean | whatsthatwordmean