Depends where you plan to go..North India is hot during those months..especially New Delhi, Agra, Rajasthan (Jaipur, Udaipur) etc.. The max temp rises to 110 F or like 47 deg celcius. Be prepared to travel with cotton, water and sun screens and travel in AC coaches (train and buses) and stay at nice hotels…Monsoon hits southern India during that time, so traveling to Bangalore, Kerala, Mumbai is bad too!!
I say the best places to visit that time is HImalayas (Kashmir, Nepal) or foot hills of Himalayas like Kullu Manali, Shimla, etc..I am sorry that I wasn’t of much help here..if you can travel in April or May then would be nice..