Spring is here and with it warmer weather, flowers and, of course, fireballs.

For reasons scientists have yet to fully understand, spring is fireball season for planet Earth, which means the nightly rate of sitings suddenly jumps from 10 percent to 30 percent.

All told, NASA reports that a person with the time and patience to sit and stare into Space from dusk until dawn could witness as many as 10 of these meteors brighter than the planet Venus shoot past the night sky.

And it's not just fireballs - meteorite falls are more common during this time of year as well.

But, as mentioned before, the reason for the phenomenon, which has been observed for over 30 years now, is still a mystery for scientists.

In fact, the more they've examined it, the stranger it gets.

The apex of the Earth, or the direction the planet travels, is comparable to the windshield of a car. And, like a car, the Earth's apex often picks up debris as it moves - only instead of bugs, its meteoroids.

Every autumn, the apex climbs to its highest point in the sky and, as a result, is a time of abundant sporadic meteors.

But, asks Bill Cooke of NASA's Meteoroid Environment Center, if fall is sporadic meteor season, "why are the sporadic fireballs peaking in spring? That," he says, "is a mystery."

Peter Brown of the University of Western Ontario explains that some scientists believe this may simply be the result of an intrinsic variation in meteoroid population along Earth's orbit, and that spring marks the period during which our planet crosses through the thickest patch of it.

And while most annual meteor showers, such as the Lyrids, are largely composed of dust and sand-sized particles, these fireballs appear to be larger in size.

But, Brown says, researchers "won't know the answer until we learn more about their orbits."