Perth's wettest days (for the Perth Metro weather station) 1. February 10, 2017 - 114.4mm 2. January 22, 2000 - 104mm 3. June 10, 1920 - 99.1mm 4. January 15, 2018 - 96mm 5. July 29 1987 - 95mm. Tuesday: 19 - 31, showers and the chance of a thunderstorm. Wednesday: 21 - 28, light rain easing. Thursday: 19 - 28, possible morning drizzle