This summer was Busselton’s wettest on record in 100 years.
The total summer rainfall for Busselton Aerodrome was 96.2 millimetres.
Bureau of Meteorology climate expert Glenn Cook said these results for a summer season were uncommon.
“The City of Busselton has rainfall records back to 1880,” he said.
“The recorded 92.9 mm in summer of 2017-18, which is its second wettest summer on record, is only behind 116.9 mm in summer 1917-18.
“So such a wet summer is very unusual.”
Only 32 summer days were recorded as 30 degrees or above, which is well below the 41 day average.
Mr Cook said temperatures also failed to reach their usual peak.
“The last time Busselton recorded less than 32 days at or above 30 degrees in summer was the summer of 2005-06 with a total of 27 days,” he said.
“Thirty two days is the second lowest total since records commenced at Busselton Aerodrome in 1997.
“So on average, this type of mild summer has occurred once every 10 years or so in recent decades.”
Mr Cook said the autumn outlook suggested above average temperatures for the South West.
State-wide, summer rainfall was above average across most of WA.
The State-wide mean maximum temperature was below average while the mean minimum temperature was above average.
Summer rainfall was the tenth-highest on record for WA due to the passage of tropical cyclones Hilda, Joyce, and Kelvin, and a tropical low producing a string of moderate to heavy falls over much of the state.