Highest, coldest, and rarest clouds on Earth are returning- How to view the strange "noctilucent clouds"

Over the next several months, look up an hour or two after sunset and before sunrise to see ethereal blue, silver, or golden streaks in the Northern Hemisphere’s northern skies. These strange-looking patterns in the sky, known as noctilucent clouds or NLCs, are the highest, driest, coldest, and rarest clouds on Earth.