The largest city of not just Assam, but also the entire Northeast India, Guwahati has a number of tourist attractions such as Kamakya Temple, Assam State Zoo and Umananda Temple. You can get the lowest flight fare from Guwahati (GAU) to most parts of the world too. You will have to take your flight from Lokpriya Gopinath Bordoloi Airport, which is a primary international airport in the Northeast.
After performing Hajj, if you have some time on hand, visit the National Museum, Kingdom Center, Diriyah and Owais Souq. You can book cheap flight tickets to Riyadh (RUH) all year round from any part of the world. Your flight will land in King Khalid International Airport, which is just 32 km north of the city. The best time to visit would be between November and February.