Tbilisi’s weather is uniquely defined by its geography, nestled in a valley formed by the Kura (Mtkvari) River and flanked by the Trialeti Range and the Saguramo Mountains. This position creates a humid subtropical climate with significant continental and semi-arid influences, resulting in distinct seasons and fascinating local variations.
Typical Weather Patterns
Tbilisi experiences four well-defined seasons. Unlike the humid Black Sea coast to the west, Tbilisi is notably drier. The city’s climate is a tug-of-war between dry, continental air masses from Central Asia and Siberia to the east and moist, oceanic air masses from the Atlantic and Black Sea to the west. This competition often results in clear, sunny stretches followed by sudden, localized shifts in atmospheric pressure.
Daily Climate Behavior
In most seasons, Tbilisi exhibits a noticeable diurnal temperature range, often swinging 10–12°C (18–22°F) between day and night.
- Morning: In spring and autumn, mornings are often crisp and clear. In summer, the early hours provide the only respite before the heat builds in the valley.
- Afternoon: This is when the "valley effect" is most pronounced. In July and August, heat becomes trapped between the surrounding hills, reaching its peak around 3:00 PM. In late spring (May and June), the afternoon is the most likely time for heavy thunderstorms.
- Evening: As the sun sets, a cooling breeze often rolls down from the surrounding mountains, a phenomenon locals highly value for making summer nights bearable.
Seasonal Trends
- Spring (March–May): This is the most unpredictable season. While March can still feel wintry with occasional sleet, May is the wettest month of the year. The landscape turns vibrant green practically overnight, but travelers should expect frequent afternoon rain showers.
- Summer (June–August): Summers are hot and largely dry. Temperatures frequently exceed 30°C (86°F) and can spike to 40°C (104°F) during heatwaves. The air feels heavy in the city center, which lacks the cooling sea breeze found on the coast.
- Autumn (September–November): Often considered the golden season, autumn is stable and glorious. September and October offer warm, sunny days and mild nights with very little rainfall. The "Velvet Season" in late September is a highlight for many visitors.
- Winter (December–February): Winters are moderately cold and notably dry. While the surrounding mountains are buried in snow, the city center rarely sees more than a light dusting that melts quickly. January is the coldest and driest month.
Microclimates and Variations
Tbilisi’s elevation ranges from 380 to 770 meters (1,245 to 2,525 feet) above sea level, creating distinct microclimates.
- Vake and Saburtalo: These lower-lying districts can feel several degrees warmer and more humid during the summer.
- Mtatsminda and Sololaki: The higher-elevation neighborhoods on the hillsides are consistently cooler. On a hot July day, the temperature at the top of the Funicular (Mtatsminda Park) can be 3–5°C lower than in the city center.
- The Tbilisi Sea: This large reservoir in the suburbs creates a localized humid zone and often experiences stronger winds than the sheltered Old Town.
Historical Context and Local Experience
Historically, the Greater Caucasus range to the north acts as a shield, blocking the most severe arctic air from Russia. This protection makes Tbilisi significantly milder than cities at similar latitudes in the US or Central Asia.
Locals adapt to the rhythm of the city by retreating into the shaded courtyards of the Old Town during summer afternoons. The "Tbilisieri" (local wind) is a common topic of conversation; when the wind picks up, it typically signals a change in weather—either blowing away the summer smog or signaling an incoming winter front.
Atmospheric Phenomena
- The Valley Heat Trap: During summer, the city can suffer from an "urban heat island" effect, where the stone buildings and narrow streets retain heat long after the sun goes down.
- Mountain Thunderstorms: In May and June, the clash of air masses over the Caucasus often triggers dramatic, fast-moving electrical storms that provide temporary relief from the humidity.
- Dry Winter Winds: The winter is characterized by the "Shavi Kari" (Black Wind) or "Tetri Kari" (White Wind), which are strong, gusty winds that can make the moderate temperatures feel much colder than the thermometer suggests.