The Bureau of Meteorology recorded just 6.9 degrees about 4.30am in the River City but it was nowhere near the coldest Brisbane morning on record, which stands at 2.5 degrees.

The Scenic Rim town of Beaudesert got down to minus 0.4 degrees on Saturday, with BoM meteorologist David Crock saying large parts of the state were colder than expected.

"This morning was little cooler than we were expecting ... anywhere up to Bundaberg, most places were a little cooler than forecast," he said.

"Monday morning could be slightly cooler than today, but we are expecting it to be pretty similar so it won't be cooler by much."

Looking ahead, Brisbane was forecast to get overnight lows of 9 degrees on Sunday and 7 on Monday before warming up again later next week. Tops of 19-23 degrees were expected for the next week.

Stanthorpe near the state border was bracing for minimum temperatures of minus 4 degrees, minus 2 and minus 1 for the next three days.

Oakey, north-west of Toowoomba, was forecast to drop to minus 3 degrees on Sunday and hit lows of minus 1 for the three days after that.

BoM meteorologist Rick Threlfall told Fairfax Media on Friday that cool, dry air coming from south of Tasmania was predicted to make the mercury drop in Queensland and cause widespread frost.

Mr Threlfall said the south-eastern corner of the state would gradually see much cooler air arrive from the south later this weekend and into early next week.

"Cold winds are expected from the south-south-west. The air will be very dry, which allows the temperatures to fall away pretty sharply overnight," he said.

"Everywhere in south-east Queensland will see the cold air moving through.

"In combination with the cool minimums and maximums, we will get a breeze from the west ... [adding] a bit of wind chill.

"The cold air will then push further north mid to late next week. Frost will extend across the state and up into the northern tablelands, inland from Cairns."