The Bureau of Meteorology issued a severe thunderstorm warning for heavy rainfall in areas near Canberra, Yass and Goulburn just after 2pm.

Heavy rain in Tuggeranong saw about four millimetres fall in less than an hour between 2pm and 3pm, with significant falls also reported in Bungendore and the north-west suburbs of Canberra. Canberra Airport recorded less than a millimetre in the same period.

Temperatures peaked at 1.21pm on Saturday when it reached 29.8 degrees. By 4.40pm it was 21.8 degrees.

Bureau forecaster Helen Reid said a trough system over the eastern part of NSW was driving the wet conditions, with an unstable atmosphere, high humidity and high moisture leading to rain.

"We've got storms expected tomorrow, probably not so much over the ACT proper but really just along the Brindabellas," Ms Reid said. "Then there's the possibility of storms until mid next week."

Temperatures are forecast to reach 24 degrees on Monday, with a 70 per cent chance of rain.

Hail was unlikely in the ACT in the coming week but would be assessed by forecasters each day, Ms Reid said.

Meanwhile, the Corin Road reopened on Saturday after an assessment deemed it safe following the impact of the Orroral Valley fire.