Street-lighting will be temporarily affected when the clocks go back an hour on Sunday.
There are around 42,000 streetlights across the county that are switched off between the hours of midnight and 6am.
Coun Richard Davies, Executive Member for Highways, said: “Over the next few weeks, you might notice that the part-night streetlights start to go off and come on at different times.
“Please be assured that this is not due to a technical fault. The street lights have sensors that monitor the number of daylight hours, which is how they set their internal clock.
“During the autumn, the lights enter a period of adjustment, when their timings may vary as they adapt to the switch to Greenwich Mean Time.
“Unfortunately, this is unavoidable, but it is only temporary.”