The tremor came from a major earthquake in the Banda Sea, almost 600km away.

That came from the north, the cold air is coming from the south.

Bureau of Meteorology forecaster Chris Kent said a high pressure system had pushed the cold air from the southern reaches of the continent over the past two days.

This current cold snap should be over for now.

Officially, the temperature fell to 4.6 degrees early this morning, the coldest Katherine day for 12 years.

It was the coldest morning since 4.3 degrees was recorded on June 29, 2007.

The record low is 3.2 degrees on July 28, 2001.

Records have been kept at the Tindal base where the weather is monitored since 1969.

Mr Kent said the cold air was being pushed by south-east winds.

He said the very dry air was helped by the cloudless days to produce the unusual cold spell.

The bureau is forecasting a rise to an eight degree minimum tomorrow morning.

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