Pembrokeshire has a mild maritime climate — winters are wet and grey but rarely freezing, summers are warm rather than hot, and the wind off the Irish Sea is almost constant. May and June tend to be the driest months and the light is extraordinary. September is also excellent — fewer visitors, the sea still warm enough for the brave, and the coastal heathland blooming purple with heather.
Summer school holidays (late July through August) bring the most visitors to Pembrokeshire; Fishguard is quieter than the beach resorts further south, but accommodation books up. For birdwatching at Strumble Head, autumn (September to November) is peak season for seabird migration. The Fishguard Folk Festival, held in late May, draws musicians from across Wales and Ireland for a weekend of traditional music.