Byblos is pleasant to visit year-round, but the best months are April to June and September to November. Spring brings mild temperatures (18–24°C), wildflowers on the hillsides above the city, and crowds that are still manageable. Autumn is similarly comfortable and the light on the archaeological site in October is exceptional.
Summer (July–August) is the most popular and most crowded period. Beirut residents flock to the coast on weekends, the harbour restaurants fill up, and the old souk is busiest. The heat can be oppressive in July and August — midday temperatures regularly exceed 32°C — but the sea breeze keeps the harbour area bearable. If you visit in summer, come on a weekday or in the early morning to have the archaeological site to yourself.
Winter is quiet and can be rainy, but the ruins are atmospheric in off-season grey light and the restaurants still operate. January and February occasionally see frost in the surrounding mountains, though the coast itself rarely gets below 10°C.
The Byblos International Festival, held in the archaeological site and the castle courtyard in July and August, is a well-regarded music and arts event that has attracted international performers. If your visit coincides with the festival schedule, attending a concert in this setting is a memorable experience — check the festival website for programme details.