The heavy rain forecast for Perth over the long weekend could impact crowd numbers for this year’s IGA Perth Royal Show.

This year will be the fourth in a row the show has experienced wet weather.

Figures from the Royal Agricultural Society of WA 2017 annual report indicated the wet and cold weather during the 2016 show was the main cause for a decrease in crowd numbers.

A crowd attendance of 311,000 was recorded at last year’s show, a 42,000 person decline compared to 2015.

WAFarmers media and communications officer Melanie Dunn said while the inclement weather may affect crowd numbers, people were encouraged to brave the elements and visit the show as it was a great day out for families and those interested in the state’s agricultural industries.

“Visitors can brave the elements by bringing umbrellas or wet weather gear, or can visit numerous pavilions and stalls that are sheltered,” she said.

“Please also heed the safety advice of the event organisers if they give you instructions, as the safety of visitors is their foremost concern.”

Bureau of Meteorology duty forecaster Bob Tarr said tomorrow was the best day for anyone considering attending the show over the long weekend.

“Conditions should ease during tonight and tomorrow for most areas around Perth,” he said.

“For tomorrow just expect a shower or two during the day.

“As you head into Sunday we’re expecting a low pressure system to move towards the area and during the afternoon and evening we expect some reasonably good rain with moderate falls and a chance of a thunderstorm that will continue into Monday.”

The Bureau of Meteorology issued a severe weather warning at 1.29pm for Perth and parts of the state’s south, with showers and isolated thunderstorms likely to produce damaging winds of 100km per hour or 115km per hour in coastal areas.

A spokesperson from the IGA Perth Royal Show said they were unable to comment about the impact of the weather on the show.

The show opens tomorrow and will run until September 30.