Crowds at Floriade were noticeably sparse on Sunday afternoon, with locals and tourists clinging to umbrellas or taking shelter from showers.

Weatherzone meteorologist Craig McIntosh said the rain was mostly isolated and would pass before the Monday morning commute to work.

"The rain kicked off around 10am and we had about 4.5 millimetres by 5pm, so nothing too extreme," he said. "The heaviest rainfall was between 2pm and 3pm."

"The cause of this was a low pressure system that gathered a lot of tropical moisture up north and dragged it across Canberra."

The rainfall may create extra work for head gardener and 19-year Floriade veteran Andrew Forster, with many taller flowers bent and damaged by conditions.

Some tourists may have noticed the addition of portable flower beds across Commonwealth Park, which were billed by the ACT government as a "game changer" for the festival.

The beds are an attempt to appease the National Capital Authority after it raised concerns the festival was damaging the parkland and may need to be moved in future years.

Only 14 landscaped designed garden beds were dug for this year's festival, which has proved a major tourist attraction for Canberra with 500,000 visitors expected this year.

The gloomy skies were a contrast to the opening of the festival on Saturday, when crowds queued at the gates before 9am to bask in sunshine and clear skies.

Mr McIntosh said Monday and Tuesday would be free of rainfall, with temperatures lingering around 16-17 degrees.

"The clearer sky will make for some cooler mornings on Monday and Tuesday as the showers disappear with overnight lows of 2 and 4 degrees," he said.

"On Wednesday we will see the return of more wet weather as another low pressure trough passes across the territory. At this stage our models are showing 5-10 millimetres of rainfall, although it could be as high was 15 millimetres."

Floriade runs for 30 days. Visit floriadeaustralia.com for details.