Cold May

The minimum temperature in Perth this month was just nine degrees, two below the long-term May average.

It was the lowest average since 1995.

Maximum temperatures weren't as notable, averaging 22 degrees, very close to the long-term average for May.

This came despite nine days in the month where the mercury stayed below 20 degrees, a feat which hasn't happened in three years.

"There were a few intense low pressure systems that crossed the west coast of Western Australian this month," said Samuel Terry, meteorologist for weatherzone.com.au.

"These brought widespread cloud and rain, dropping day-time temperatures. As well as this, cooler winds and clear skies behind these systems brought cooler nights, making it Perth's coldest May in 15 years," he said.

Perth managed to collect 89 millimetres of rain this month. It was the wettest May in five years.