NEW YORK (AP) — Dust off your eclipse glasses: It’s only a year until a total solar eclipse sweeps across North America.

On April 8, 2024, the moon will cast its shadow across a stretch of the United States (US), Mexico and Canada, plunging millions of people into midday darkness.

It’s been less than six years since a total solar eclipse cut across the US, from coast to coast. That was on Aug. 21, 2017.

If you miss next year’s spectacle, you’ll have to wait 20 years until the next one hits the US But that total eclipse will only be visible in Montana and the Dakotas.

Next year’s eclipse will slice a diagonal line across North America on April 8, which falls on a Monday.

It will start in the Pacific and first reach land over Mexico around 11:07 a.m. local time, NASA predicts. Then, it’ll cross over into Texas and move across parts of the Midwest and Northeast in the afternoon.

All in all, it will hit parts of 13 US states: Texas, Oklahoma, Arkansas, Missouri, Illinois, Kentucky, Indiana, Ohio, Pennsylvania, New York, Vermont, New Hampshire and Maine. Cities in its path include Dallas; Little Rock, Arkansas; Indianapolis; Cleveland and Buffalo, New York.

Parts of Canada — including Quebec and Newfoundland — will also get a glimpse before the eclipse heads out to sea in the early evening.

A total eclipse will be visible within a 115-mile wide swath — the path of totality. Outside that path, you can still see a partial solar eclipse, where the moon takes a bite out of the sun and turns it into a crescent shape.

Total eclipses happen about every 18 months, but a lot of times they cross over remote areas where few people see them.

Solar eclipses occur when the moon passes in between the Earth and the sun, blocking the sun’s light from reaching us.

Even though the moon is about 400 times smaller than the sun, it’s also about 400 times closer to Earth, explained University of Colorado astronomer Doug Duncan. So when the orbits line up just right, the little moon can block out the whole sun. Those who are standing in the right spots will experience totality: when the moon casts its shadow over the landscape.

“In just seconds, you go from bright, bright daylight to like the middle of the night,” said Dr. Debby Brown, who saw her first total eclipse in 2017 with Duncan in Grand Teton National Park in Wyoming.

“The stars are out. All of a sudden, all the animals are quiet,” recalled Brown, of Arlington, Virginia.

During the 2024 eclipse, totality will stretch to around four and a half minutes — almost twice as long as in 2017.