Spring (May–June) and autumn (September–October) are the best times to visit. Temperatures are mild, the countryside is green or golden, crowds are manageable, and in autumn the wine harvest in Kakheti gives the country a particular energy.
Summer (July–August) is hot — uncomfortably so in Tbilisi and the lowlands, where temperatures can hit 38–40°C. The mountains and the Black Sea coast are the places to be. Kazbegi and the high Caucasus are at their best in July and August, with snow-free trails and long days. This is the only time to reliably hike at altitude.
Autumn (September–October) is arguably the finest season. The heat has broken, Kakheti's vineyards turn gold and the harvest is underway, and Tbilisi is at its most sociable. Bring a layer — evenings cool quickly.
Winter (December–February) is cold in Tbilisi but not brutal. Streets are quieter, prices drop, and the sulfur baths are especially appealing. Orthodox Christmas (7 January) and New Year are festive. Bakuriani has ski slopes if snowfall cooperates. Avoid mountain routes in winter unless you know what you are doing.
Spring (March–April) is pleasant but can be rainy. By May things have opened up properly and travel is comfortable.
Georgia's climate varies significantly by region. The west (Adjara, Colchis) is subtropical and wet year-round. The east (Kakheti, Kartli) is drier and more continental. The mountains follow their own rules regardless of season.