Daylight saving will bring an extra hour of evening sun when it starts in some Australian states this weekend.
Residents in NSW, Victoria, Tasmania, South Australia and the ACT will move their clocks forward one hour, and miss an hour of sleep when the annual change occurs at 2am on Sunday, October 6.
Daylight saving means Australia's three standard time zones split into five, while Western Australia falls three hours behind those states that observe DST.
Dr Sveta Postnova from the University of Sydney's School of Physics said the time change can impact our sleep and circadian rhythm longer than the initial one hour lost overnight.
"Experimental data suggests a cumulative effect of sleep loss lasting for at least the following week and sometimes longer," Dr Postnova said.
Most smartphone devices and computers automatically adjust the time but analogue clocks need to be changed manually.
A way to remember how to change clocks for daylight saving is 'spring forward" at the start, and when it ends in autumn, it's "fall back'.
© AAP 2019