Heavy rain and thunderstorms have been forecast to hit Wales this weekend which could lead to travel disruption and flooding, the Met Office has said.
A yellow "be aware" warning is in place from 06:00 BST on Saturday and will run until 23:59 on Sunday.
Events such as the Biggest Weekend in Swansea could be affected while there is the risk of properties being damaged by floodwater, lightning strikes, hail or strong wind.
Public transport may also be affected.
The warning covers the whole of Wales, and the Met Office said there is a chance that fast flowing or deep floodwater could cause danger to life.
People travelling for the bank holiday weekend have also been warned that spray and sudden flooding could lead to difficult driving conditions, and possible road closures.
Some communities may be cut off by flooded roads and there is a chance that power cuts will occur during the worst of the weather.