The summer solstice occurs at 10:42 P.M. EDT, marking the official beginning of summer for those in the Northern Hemisphere. On this date, the Sun is located directly above the Tropic of Cancer at 23.5° north, taking its most northerly path through the sky. It is also the longest day of the year north of the Tropic of Cancer.
Although the night is short, it’s still an excellent opportunity to try viewing a summertime phenomenon called noctilucent clouds. These clouds are unusual in that they form very high in the atmosphere, when ice crystallizes around aerosol particles some 50 miles (80 km) high — that’s roughly 10 times higher than the more familiar cirrus clouds. To see them, look toward the north. Your chances are higher if you live at a higher latitude, as these clouds are most often seen by observers between about 50° and 65° north, though this is not a hard cutoff.
Noctilucent or night-glowing clouds appear exactly that — to glow long after the Sun has set. This is because they’re floating so high up that sunlight reflects off them long after sunset from an observer’s location, thanks to the curvature of Earth. These clouds can be visible even around midnight, offering a dazzling show even if the stars aren’t visible. You’ll know you’re seeing noctilucent clouds because of their glow, rather than the dark blotches associated with much lower clouds. And although these clouds appear static over short periods of time, if you spend a while watching or photographing them, you’ll see their shapes transform, ebb, and flow throughout the night.
Sunrise: 5:31 A.M.
Sunset: 8:32 P.M.
Moonrise: 1:39 A.M.
Moonset: 3:22 P.M.
Moon Phase: Waning crescent (29%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. local time from the same location.
For a look ahead at more upcoming sky events, check out our full Sky This Week column.
