Summer (June-August): Peak season with the best weather. Temperatures range 15-25°C (59-77°F) with long daylight hours up to 19 hours in June during White Nights. Perfect for outdoor activities, beach visits, festivals, and terrace dining. Old Town buzzes with tourists, prices peak, and advance booking essential. The medieval Old Town Days festival in July brings markets, performances, and historical reenactments.
Spring (April-May): Excellent shoulder season with blooming parks, fewer crowds, and moderate prices. Temperatures 5-15°C (41-59°F). Kadriorg Park bursts with spring flowers, particularly stunning in May. Weather can be unpredictable with occasional rain. Many attractions open for season, outdoor cafes resume, and the city awakens from winter.
Autumn (September-October): Another ideal shoulder season. September often has beautiful weather (10-15°C/50-59°F) with golden autumn colors, harvest festivals, and fewer tourists. October brings cooler temperatures and more rain. Cultural season begins with theater, concerts, and exhibitions. Restaurant Month in November offers special dining deals. Days shorten rapidly by October sunset comes around 6 PM.
Winter (November-March): Cold and dark but magical for Christmas markets and winter atmosphere. Temperatures -5 to 0°C (23-32°F), sometimes colder. Tallinn Christmas Market (November-January) is one of Europe's best, transforming Town Hall Square into a winter wonderland with crafts, mulled wine, and festive atmosphere. Snow covers medieval streets, creating fairytale scenes. Shortest day (December 21) has only 6 hours of daylight. Budget season with lowest prices and authentic local experience.
Best Overall: Late May-early September for weather and activities. December for Christmas markets and winter magic. September for fewer crowds with good weather.