For the 40th anniversary of Earth Day, nature will be setting off some fireworks, with the peak of the annual Lyrid meteor shower arriving on April 22.

While the Lyrids might not be cosmic celebrities like August's showy Perseids, the April meteor shower has been known to offer up a surprise or two for sky-watchers

(Related: "Comet 'Shower' Killed Ice Age Mammals?")

"Although the Lyrids have been observed since 687 B.C., the behavior of the shower from year to year is unpredictable," said Anthony Cook, an astronomer for the Griffith Observatory in Los Angeles.

"An average Lyrid shower produces between 10 and 20 meteors per hour, but occasionally these rates increase to 90 per hour," Cook said. "In 1803 the shower produced about a thousand meteors per hour"—just enough to qualify as a meteor storm.

How to See the Lyrid Meteors

This year, Lyrid meteor activity began picking up on April 16, and the shower will run until April 25.

The Earth Day peak will actually come in the early morning hours of April 22, after the first quarter moon has sunk below the horizon, leaving dark skies. (Test your lunar smarts with our moon quiz.)

"The best time to look will be between the time of moonset [between 1 and 2 a.m., local time] and dawn, and the best way to observe the show is to recline comfortably, facing anywhere from north to east and gazing nearly overhead," Cook said.

"The best location is a region far from urban light pollution with a fairly open horizon."

Lyrids to Be a Sprinkle or a Storm?

The Lyrids' "shooting stars" will appear to radiate from around the brilliant star Vega in the shower's namesake constellation Lyra.

Vega now shines nearly overhead in the predawn hours for stargazers in the Northern Hemisphere. In the Southern Hemisphere skies, the Lyrids will produce just a sprinkling of meteors.

As with other annual meteor showers, the Lyrids are thought to be caused by debris left over from a passing comet. When Earth passes through the trail of particles—most no bigger than grains of sand—the tiny rocks burn up in our atmosphere, creating bright streaks.

(Related: "'Major,' Green Meteor Lights Midwest Night Sky," with video.)

The Lyrids have been linked to the periodic comet Thatcher, which has an orbit that's skewed nearly perpendicular to the plane of the solar system, the tabletop-like plane along which the planets orbit.

The dearth of planets along the comet's path means that its debris trail stays relatively stable, which is most likely why the Lyrids have been a reliable meteor shower for centuries.

But sometimes Earth passes through a particularly dense clump of cometary leftovers, and that's when meteor rates skyrocket.

So are sky-watchers this year in for a sprinkle or a storm?

"The only way to know what the Lyrids have in store for you," Cook said, "is to go outside and observe them."