Glass Butter Beach was supposed to run from Friday to Sunday at Abersoch, Gwynedd.
But organisers have cancelled Saturday's event due to "extremely severe weather conditions."
A yellow "be aware" warning is in place for every council area in Wales until 21:00 BST Saturday with heavy showers expected.
A message on Glass Butter Beach's Facebook page on Saturday said: "In light of today's extremely severe weather conditions, we are unable to open the main arena and the festival for today has unfortunately been cancelled."
The programme is set to go ahead as planned on Sunday. Saturday tickets will be valid for Sunday's programme.
The Met Office warned gusts of up to 60 mph could hit most of Wales on Saturday.
Coastal areas face the strongest winds, which will bring large waves in the most exposed places.
Flood alerts for Pembrokeshire, Ceredigion, Carmarthenshire and Swansea are also in place, with high tides predicted to last from Friday to Monday.
In Swansea, the Ride with the Pros cycle event has been cancelled because of the weather.
A three-day music festival has cancelled its Saturday programme due to strong winds and heavy rain.