A hot and dry state as such, Gujarat can be visited anytime during the year. But a perfect time for a fulfilling holiday would be the winters that are pretty decently pleasant.
Summer months: April to May. Not recommended but the lone hill station of Saputara is pretty popular in these month among the travelers.
Monsoon months: July till September. Again not very popular although, but the cities like Surat, Ahmedabad, Vadodara, Jamnagar, Saputara, Dwarka and Rajkot does see tourists during these months.
Winter months: With temperature falling down to the range of 12-27 degrees, winters is a perfect time to be at Gujarat! Be it Rann, Gir, or temples of the city, or the deserts of Rann, its an utsav altogether for the exploring eyes.
When you are here, you would be marveled by the simplicity that these people have to offer. They are colorful, vibrant, warm, traditional and peace loving. The very popular festivals of the state are the kite festival, Uttarayan, Modhera Dance Festival, Kutch Utsav and Holi. Witness the fervor during the nine nights of Navratras. Each night of this festival people gather together in open spaces to dance and celebrate (ras garba is the dance form). You would be amazed to witness the people whirling in circles together with rythmic steps as late as upto 2AM every day!
So when you are here, you would love to stay here, for its the Khushboo Gujarat Ki that will not really let you go!