The Department for Transport says its "disappointed" that 4,000 members of staff have decided to strike today.
The PCS union says members will hold 15 minute demonstrations across Wales.
We are disappointed that the PCS union have decided to take industrial action while we are still engaged in consultation with them about their concerns over changes within the department.
Contingency plans are in place to ensure delivery of essential services to the public continues throughout the planned strike action.
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It will quickly turn chilly for many this evening, but it will stay milder in the west.
Gerald Corrigan is in a critical condition after being hit while fixing a satellite dish in Holyhead, in the early hours of Friday morning.
The sunshine will become hazy at times, but will remain strong.