Baalbek sits at around 1,170 metres altitude in the Bekaa Valley, which gives it a continental climate quite different from the coast. Summers are warm and sunny but not oppressively hot — highs around 28–32°C from June to August. Winters are cold, with snow possible from December to March, and the mountain roads can be challenging.
The best time to visit is late spring (April–May) or early autumn (September–October), when the weather is pleasant, the light is good for photography, and the crowds at the ruins are manageable. The ruins look spectacular in late afternoon light.
The Baalbeck International Festival runs through July and August, filling the temple complex with concerts and performances. If you want to combine a ruins visit with the festival, this is the time to come — but book accommodation and festival tickets well in advance.
Ramadan is worth bearing in mind: restaurants may have limited hours and the town's atmosphere changes, though the ruins remain open.