Don't get caught out by Canberra's false spring.
The temperature fell below freezing point in the capital for the first time this month on Monday morning, as the mercury plummeted to minus 2.4 degrees at Canberra Airport, and minus 3.1 in Tuggeranong.
The cold snap came shortly after the territory experienced its warmest day since early May on Saturday, when it reached 22.2 degrees at the airport.
Bureau of Meteorology forecaster Elli Blandford said a cold front had moved through the ACT, cooling the capital down at the start of the working week.
"Clear skies and no wind allowed the temperature to drop," she said.
Ms Blandford said the temperatures were not typical of September, with the long-term average Canberra low just 3.3 degrees, and 16.2 degrees the average high.
She said it was not forecast to drop below freezing point in Canberra again this week, though it may reach zero on Thursday and Friday.
The most likely chance of rain this week will be on Sunday, when the bureau is forecasting a 30 per chance of showers.
"While, at the moment, it looks like there might be some rain on Sunday, the models are pretty up and down this far out," Ms Blandford said.