Piran weather in September
September in Piran: warm, soaked, with clean air — fine if you can take 11 rainy days.
Updated September 2026 · climate normals from ERA5 reanalysis
#4 of 12 months in Piran · #625 of 1413 destinations to visit in September · comfort 82/100 (tier A)
- Days
- 25°C
- Nights
- 20°C
- Wet days
- 11
- Sun
- 9.8 h
- Humidity
- 71%
- Daylight
- 13 h
Traveller notes on Piran in September
Notes from nearby Rovinj (50 km away)
Piran doesn't have its own notes for September yet — these are about Rovinj, close enough to share the season.
The sea is not what ends the season here. Regulars say it barely cools from August and put it near 22C - our row has 24.1C - so swimming holds up all month, and after the first week the crowds are gone. What closes is the town: by the middle and end of September bars and restaurants start shutting, and around the 20th the sun beds come in. Weather is a lottery within that, one week sunny and the next a washout. Our 145.3mm falls across only 10.2 days, fourteen millimetres apiece, so the rain when it comes is a storm rather than a grey spell. The record: 24.8C days over 16.4C nights, 10 hours of sun, a 14.9 kph wind and AQI 48.
Other months in Piran
Piran's forum agrees the sea keeps this stretch of coast milder than inland Slovenia in January, though a windy day can still feel properly cold even with the sun out. On a clear day, several posters mentioned you can see all the way to the snow-capped Julian Alps and Dolomites from town, which is worth timing a visit around. Not every restaurant stays open through winter, and most people treat Piran as a half-day stop rather than an overnight, but light snow on the roads inland is possible once or twice a month, so build in some flexibility.
Forum posters describe Piran's summer as sunny and hot with a cooling sea breeze, part of what they call a submediterranean climate - more stable and predictable than the continental weather found inland in places like Bled. A shower or thunderstorm is always possible, but posters are clear that sustained multi-day rain is unlikely, with conditions bouncing back to sun quickly after a storm passes. July counts as peak season alongside August, so warm, mostly sunny days come paired with the year's biggest crowds.
Add your own note from Piran's card on the map.
Piran climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Piran in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusyDay-tripper hours, school holidays in 3 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Piran's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherPiran's weather peaks June–August, best around July.
Best weatherFair weatherToughest weather
What's on in Piran in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Season
Secovlje salt harvest
23 Apr – 15 Sep · usuallyThe salt pans south of town are still worked by hand from St George's Day through the summer, raked into white ridges on the same beds used for six hundred years. Out of season it is a birdwatching marsh instead. Source ↗
- Season
Day-tripper hours
15 May – 20 Sep · usuallyDay-tripper crushCrowdedCars stop at the Fornace car park and everyone arrives on the shuttle, so the old town fills between about ten and five and empties completely after. Stay the night and Tartini Square is yours. Source ↗
- Season
Swimming season
15 Jun – 25 Sep · usuallySea warm enoughThe northern Adriatic is shallow here, so it warms early and cools early; you swim off concrete platforms rather than sand. September water is still fine and the town is half as busy. Source ↗
- Festival
Tartini Festival
20 Aug – 5 SepMusic festivalA fortnight of chamber and baroque music for the violinist born on the square, played in the church and the Venetian halls rather than a concert venue. Late August into the first days of September. Source ↗
Nearby, and something's on
Within 300 km of Piran — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Piran?
Piran in September — FAQ
- Is September a good time to visit Piran?
- September in Piran: warm, soaked, with clean air — fine if you can take 11 rainy days. It ranks #4 of 12 months for Piran on SeasonMap's comfort score (82/100).
- What is the weather like in Piran in September?
- In September, Piran averages a daily high of 25°C and a low of 19.7°C, with about 172.8 mm of rain over roughly 10.9 rainy days.
- What is the air quality in Piran in September?
- Piran has a mean US Air Quality Index of about 44 in September.
Within 300 km: Ljubljana's Open Kitchen food market around 15 Mar – 31 Oct, and Venice's Biennale on 9 May – 22 Nov.