A lunar eclipse, which will turn the moon a coppery red, will be occurring early Tuesday morning.
According to NASA, this will be one of the most spectacular sky events of the year, weather permitting.
The National Weather Service is calling for showers tonight.
The eclipse will begin at 1:58 a.m., with the totality occurring at 3:05 a.m.
The moon is expected to turn reddish at about 2 a.m. and remain that way for over an hour.
This begins a unique series of four eclipses, called an eclipse tetrad. The next will be on Oct. 8.
"The most unique thing about the 2014-2015 tetrad is that all of them are visible for all or parts of the USA," NASA eclipse expert Fred Espenak said in a press release.
In the 21st century, there will be many tetrads, but look back a few centuries, and you'll find the opposite phenomenon, Espenak said.
Before the dawn of the 20th century, there was a 300-year period when there were none, he said.
People in North and South America will be able to see the entire eclipse, while sky watchers in the western Pacific can catch only the last half.
The moon will be setting in most of Europe and Africa during the eclipse, so residents there probably won't see much.
NASA has set up a live web chat to answer questions about the eclipse starting at 1 a.m. Eastern Time.
The event happens right in time for the Jewish festival of Passover, which commemorates the ancient Israelites' exodus from slavery in Egypt.
According to the Bible, God cast 10 plagues upon the Egyptians, the final plague being the death of the firstborn.
The Israelites painted lamb's blood on their doorways so that this plague would pass over their homes.