On Saturday night (20/05) whilst driving home I observed a circular blue light moving through the clouds.On Saturday night (20/05) whilst driving home at 21:00 I observed a circular blue light moving through the clouds. It was an overcast/wet night and bright blue circle moved east to west through the clouds. There was no lightning etc. I do not believe it to be a satellite or plane (only small, light planes fly in this area).This occurred approximately 20km North of Bunbury, Western Australia, whilst driving South towards Bunbury. I believe object to be at approximately 30 degrees to horizon. Object was visible for a matter of seconds. Passenger confirmed sighting, believed it to be unusual.Furthermore, on Monday, 22 May, whilst heading North to work (same area), at approximately 06:45, I noticed in the sky what appeared to be a contrail. Cloud was a straight, narrow vertical line that looked very unusual and stuck out compared to the rest of the sky. The only reason I really noticed this was because of the strange events on Saturday night. I checked flight radar etc. and there were no planes in the area or nearby. As indicated previously, only small planes fly in the area - contrails etc. are VERY uncommon. Doubt this is related but thought it an odd coincidence.((NUFORC Note: Source of the report elects to remain anonymous; provides no contact information. PD))