Due to the diverse climate, you can find excellent conditions for relaxation in any season. In Georgia and other countries of Caucasus you can visit the lakes immersed in the green nature in summer, the snow-capped villages in winter, the lush nature in spring and the culture of grape harvest and wine making in autumn.
If you come for trekking the best time is from the end of May till November. High passes in the Svaneti region can be crossed anytime in June already. However, Atsunta and Chaukhi passes in Khevi and Khevsureti region can be crossed from the end of June/Beginning of July which is the most beautiful period of Hiking - spring at 2600-3000s. End of August/September is dry, perfect for clear views to summits. In the second half of September it is colder but hiking is possible and colors start to get yellow. The most beautiful yellow colors are in Svaneti/Borjomi gorge on October 15th. There are tropical/desert areas which can be visited during any season.
For skiing/skitouring the best timing is January/February. The best is the second half of January and February when the holiday season is over. However you can ski in the end of December and in March as well.