The upcoming rain should clear the smoke, according to the Bureau of Meteorology.
Falling water would gather the small particles from the fires and bring them to earth.
But forecaster Helen Kirkup warned that the rain likely from Thursday onwards might well be "hit and miss", with some areas getting a downpour and others nearby being virtually untouched.
"Someone could get 20 millimetres and someone else only two millimetres," she said.
On Tuesday afternoon, the ACT government described the air quality as "poor" at all its three monitoring stations - in Monash, Civic and Florey.
They all had a similar Air Quality Index of 136 to 139 (a measure of particles in the air).
But even though the smoke remained in Canberra, the index was way down from the worst 10 days ago. Some residents wondered if the air quality was varying across the city but there was no evidence of that from the readings.
The source of the smoke may have changed with the wind, though. And it may be higher in the atmosphere.
According to the bureau, the wind now seemed to be coming from the fires to the west - Adaminaby, Dunns Road and Mary's Hill - rather than from the North Black Range fire near Braidwood.
The forecaster said that the change would take the smoke higher, over the Brindabella Range, and so higher over Canberra.
But rain will be the thing.
The bureau is forecasting some chance of rain on Wednesday, possibly thunder, but a greater likelihood on the four days after, closing out the weekend.
It also said that rain might pollute with "ash, dust and other material from your roof washing into your tank."
On Sunday, the ACT Emergency Services Agency was not holding out much hope of rain dousing fires for good - so the smoke may eventually return if fires flare up again.