The weather in India is best from November to March, and most tourists come in the first half of this high season. Delhi, a city of extremes, is often scorching from mid-April through June, and damp and cold—sometimes freezing—in December. The monsoon's daily rains, sweeping up from the southwest, usually arrive in Mumbai in June and hit Delhi a month later. Although you can work around the monsoon rains, they can lead to flooding, which makes traveling slow and sometimes even dangerous. The five days of Diwali, one of India's biggest festivals, fall in mid-October and mid-November; make reservations well in advance if you're visiting during this time or around Christmas.