Wetter in Tallinn im September

Regulars are consistent this month is genuinely hard to predict even by Baltic standards, capable of pleasant, mild stretches especially early on or a run of chill wind and heavy rain with little warning either way. Our row backs that cool, genuinely wet read, 17.1C over 9.5C nights feeling 7C, with 69.6mm of rain across 9.9 days and humidity at 81 percent. Regulars are specific that snow is not a realistic concern this early, the real planning issue is rain and wind rather than cold, and that packing both rain gear and some lighter layers covers most of what the month can bring. Regulars are consistent the Old Town stays genuinely worth walking regardless, umbrella in hand. The sea sits at a cool 17.7C. The record: 8.3 hours of sun, a 21.6 kph wind and AQI 41.

Regulars describe May here as genuinely unpredictable within a single day, one visitor recalling rain, strong wind, hail, sunshine and a swing from 15C to 25C all inside a few hours. Our monthly row averages that volatility down to 16.4C reading as 14C over 5.6C nights feeling 2C, with 32.7mm of rain across 5.9 days and a trace of snow, 0.3cm, still possible early in the month. Their consistent call is that mid to late May is the nicest stretch of the year here, cool being just as likely as warm rather than a given either way. Pack rainproofs and a t-shirt both, and a jacket for evenings regardless of how the day went. The sea stays cold at 7.9C. The record: humidity 66 percent, 13.1 hours of sun, an 18.8 kph wind and AQI 61.

Regulars point at late August rather than August: the European school terms restart, people go back to work, and the city thins while the weather still holds - once September starts they call it less predictable. The other half of the advice is hourly, not weekly. The ship tours work the old town through the day and are gone by late afternoon, so an early morning or an evening there is a different place from a midday one. Our row gives 21.8C days over 13.1C nights with 99.5mm across 11.4 days, 11 hours of sun inside 15.5 of daylight, and a 19.9C sea. The record: humidity 78 percent, a 20 kph wind and AQI 44.

July is Tallinn's warmest month and the one regulars name, with summer averages around 20C rising to 30 in a hot spell and visitors reporting 23 to 27 - our row gives 22.7C days over 13.7C nights - though they add that cool weather with rain is not unknown. June and July are the sunniest months, and our row's 13.2 hours of sun under nearly 18 hours of daylight is why their best advice is about timing rather than packing: the long evenings are the nicest part of the day for seeing the Old Town, which is otherwise fairly crowded through July and August. The record: 10.4 precipitation days carrying 69.2mm, humidity 75 percent and an 18.2C sea.

Tallinn forum threads describe January as cold and genuinely snowy, with typical temperatures cited between 0 and -15C, though posters noted a preceding cold snap once reached -27C the week before a January visit, illustrating how much the range can shift. Recent winters were described as the snowiest in a while, with posters specifically recommending late January for the best chance of fresh snow cover on the ground. Daylight was flagged as genuinely short and dark through December and January, though posters noted the light noticeably lengthens as the month goes on. Despite the cold and dark, posters were consistently positive about a January visit - many called it their favorite season here, with the snow-covered Old Town looking genuinely beautiful and none of the cruise-ship crowds that clog the streets in summer.