Plan from Mid-November to Mid-Feb when Rann Utsav is organized. It's worth to visit white desert in this time. Also you can visit near by other places. You can chcek on www.rannutsav.com
they have already started bookings. But I'm not sure about this year's possibility.
If you have a plan to visit Kutch without doubt I can say you to explore in the month of October to February. This is really a best time to visit Kutch with pleasant weather and perfect sightseeing.And one more advantage of visiting these months would be a great Rann Utsav festival will start at these months only. There will be a plenty of things to do.