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Once regarded as harbingers of doom, fiery meteors are believed to strike the Earth at complete random.

But a new study into impact trends suggests meteor strikes are more likely to occur at certain times of the year and at certain locations.

The Spanish study found that the frequency of impacts was higher when Earth's orbit took it through streams of meteoroids created by the break-up of a comet.

The Chelyabinsk meteor (pictured) was caused by a near-Earth asteroid that entered Earth's atmosphere over Russia on 15 February 2013. Scientists now believe events such as this are not as random as once thought

Most of the meteors analysed as part of the research also hit the Earth in the second half of the year, according to the University of Madrid.

'This lack of randomness is induced by planetary perturbations, in particular Jupiter's, and suggests that some of the recent, most powerful Earth impacts may be associated with resonant groups of Near Earth Objects and/or very young meteoroid streams,' the study claims.

Planets and moon can affect meteors, pushing them into orbits called 'resonant streams'.

Researchers looked at 33 multi-kiloton impact events from 2000 to 2013 that were detected by infrasound acoustic pressure sensors.

Most of the meteors analysed as part of the research hit the Earth in the second half of the year, according to the University of Madrid. Pictured is the part of the large meteor that hit Russia in 2013

The sensors are designed to detect secret nuclear tests, but also pick up meteor impacts with when they have an explosive energy in excess of a thousand tonnes of TNT.

They found 17 impacts took place in the northern hemisphere and 16 in the south.

Of these impact, 25 took place within 40 degrees north or south of the equator, while eight took place at higher latitudes.

Twenty impacts across the second half of the year were recorded compared to just 13 hits in the first six calendar months – a 21 per cent difference in timing.

In the southern hemisphere, June was the most likely month for a meteor to hit the Earth, while September and October were the least likely.

In the southern hemisphere, June was the most likely month for a meteor to hit the Earth (artist's impression pictured), while September and October were the least likely

Overall, 12 meteor impacts took place in the second half of the year compared to four in the first six months.

North of the equator, November was the most likely month for a meteor hit while May and June were the least likely. Nine meteors hit Earth in the first half of the year and eight in the second half.

'What we had always assumed up until this paper, was that meteor impacts were random, occurring at any time and in any place,' Dr Simon O'Toole of the Australian Astronomical Observatory told ABC Science.

But more data is needed. 'It's a very interesting paper, but 33 events is a statistically small sample range,' said Dr O'Toole.

556 FIERY ASTEROIDS HAVE HIT OUR ATMOSPHERE IN PAST TWO DECADES

Collision course:  Map shows the number of asteroids striking Earth's atmosphere over a 20 year period

A flash of light from a fiery asteroid is often treated with intrigue when it is spotted on Earth.

But scientists at Nasa suggest that asteroids are smashing into the Earth's atmosphere at a higher rate than most people realise.

According to a new map by the space agency, it's a wonder we don't see fireballs raining down from the skies more frequently.

The map from the space agency's Near-Earth Object Program, reveals that more than 556 space rocks smashed into the atmosphere over a 20-year period between 1994 and 2013.

The orange dots on the diagram show the frequency of asteroids that hit locations during the day while the blue dots show those that hit at night. They are measured in billions of Joules (GJ) of energy.

Most space rocks were small and harmless and disintegrated when they hit the atmosphere. Yet there are exceptions.

Last year on February 15, an asteroid which was 55 feet in diameter with a mass of up to 10,000 tons crashed to earth in the Urals region in Russia.