The Bureau of Meteorology forecast up to 40 millimetres of rain to fall, mostly in the morning, but by 6pm about 18 millimetres were recorded in the city and only about 25 millimetres had been recorded, although those totals were expected to rise with late showers forecast that night.

A few light showers were expected late in the afternoon, but the early rain was enough to cause Floriade to close for the day and Nightfest to be cancelled on Thursday night.

The bureau issued the warning for the ACT and surrounding areas after forecasting winds averaging 50 to 70 kilometres an hour with peak gusts of more than 90 km/h for Thursday morning, coming from the far west of New South Wales.

But the warning was cancelled around 11am, after winds were lighter than expected, reaching only 43 km/h around 10am.

In Canberra, emergency responders were working early in the morning with ACT State Emergency Service workers attended 14 jobs as of 6.30pm.

Most of the calls were to repair leaking rooves and fix minor electrical issues.

ACT SES had reported electrical threats in Downer, Latham and in Page, which were earlier thought to be fallen powerlines.

However, ActewAGL said the lines were not down, and had not reported any power outages in Canberra, and an ActewAGL spokesperson reminded people to stay clear in the event of a fallen powerline or damaged electrical equipment.

The severe weather warning had been issued as a fierce low pressure system and associated cold front moved through NSW, bringing widespread rain, showers and isolated thunderstorms.

The bureau's duty forecaster Sarah Chadwick said a few more millimetres of rain was expected overnight on Thursday, followed by up to 20 millimetres on Friday.

"They'll mostly be in the morning and will be easing in the evening, followed by a couple of showers on Saturday," she said.

"There's a slight chance of some shower activity in the afternoon on Sunday and throughout Monday as well."