Travelling from most locations, it is best to book your flight to Tbilisi during the month of January for the best deal, although there are other times of the year which offer great deals as well.
In general, most flyers find the cheapest time to book a flight to Tbilisi is about 57 days prior.
In general, booking your departure to Tbilisi for a Thursday represents the best deal on airfare. Try to avoid a Saturday departure to stay away from the highest prices.
On average you can find the best deals on plane tickets to Tbilisi when looking for flights with morning departure times.