The Bureau of Meteorology says the risk of cyclone activity along Western Australia's north-west coast will increase in the week before Christmas.
The cyclone season began on November 1.
The bureau's outlook is for about five tropical cyclones to form off the WA coast this season, including one or two that could hit the mainland.
The bureau's manager of severe weather services, Andrew Burton, says the modelling shows the cyclone risk will increase as Christmas approaches.
"That is typically around the time when we do see the first cyclone off the north-west coast but the guidance is now indicating that it's even more than the usual risk of seeing our first cyclone around that time," he said.
© ABC 2012
11:16 EDT Thick fog engulfed the Sydney Basin on Saturday morning dropping visibility as low as 100m in some suburbs.