It may look like a clear, sunny autumn day outside but a severe weather warning has been issued for parts of the Perth metropolitan area and locations just north and south of the city for Saturday night.

Residents should prepare for "damaging" and "unusually strong" winds.

A Bureau of Meteorology spokesperson said easterly winds of this strength generally occurred once every two to three years.

"Tonight's winds are likely to be unusually strong and may cause damage to property and make road conditions hazardous," they said.

"Damaging winds with gusts up to 100 kilometres per hour are possible and could cause damage to homes and property."