Space Debris Office in Darmstadt, Germany, which issued the Tiangong-1 prediction, said the March 30 to April 2 window is "highly variable", and it will not be possible to determine exactly where the space station will fall to Earth.
The Tiangong-1, or "Heavenly Palace" lab, will hit the earth between March 31 and April 4 and "should" burn up in the atmosphere, Chinese space officials said this week.
The European Space Agency (ESA) which has provided regular updates on the Tiangong-1, predicts re-entry "will take place anywhere between 43ºN and 43ºS" which covers a vast stretch north and south of the equator.
In the past, there have been several crash landings of space stations, including NASA's 77-tonne Skylab in 1979 and the Soviet Union's 20-tonne Salyut 7 space station in 1991, but there haven't been any casualties.
It was always expected to fall back to Earth. "Based on Tiangong-1's inclination, however, we can confidently say that this object will reenter somewhere between 43° North and 43° South latitudes".
Aerospace Corporation has played down fears, saying the fragments are most likely to fall into the ocean with the chance of a person being hit less than one in 1,000,000,000,000.
Tiangong-1's potential re-entry areas.
But the odds of the craft hitting anyone is very low, as much of it will disintegrate when it hits the Earth's atmosphere.
Experts said it's hard to establish exactly where the space lab will fall, but it's expected to descend within a latitude of 43 degrees north and south of the equator. In 2016, China announced it had lost contact with Tiangong-1 and could therefore no longer control its direction, making predicting where it will end up hard. The interest surrounding the free-falling doomed space station is the fact that scientists and researchers truly can't nail down when and where it will enter.
At around 19 tons each (17 metric tons), even the nose cones and prototype command modules of the early Apollo tests were bigger than Tiangong-1 when they de-orbited, uncontrolled, throughout the 1960s.
Heavens-above, a satellite tracking site recommended by Jonathan McDowell, an astrophysicist at Harvard University, can tell you when you can see Tiangong-1 passing in the sky above your city, and which direction it's moving in.