Most of Tibet is a high-altitude desert plateau over 4000m (13,123ft) and many passes exceed 5000m (16,404ft). Days in summer (June to September) are warm, sunny and dry, from low to mid 20°C (70-75°F), but temperatures drop quickly at night. Winter is not as cold as you might expect, still averaging around 7°C (44°F) during the day in January but plunging to around -10°C (14°F) at night. The best time to visit depends on what part of Tibet you're heading to, but for most areas May, June and October are the best months.