SeasonMapHeidelberg weather in September
Germany
September in Heidelberg: nice, a little rain, with clean air — one of the best months to visit.
#1 of 12 months in Heidelberg · #172 of 1383 destinations to visit in September · comfort 91/100 (tier S)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Heidelberg in September
Notes from nearby Baden-Baden (79 km away)
Heidelberg doesn't have its own notes for September yet — these are about Baden-Baden, close enough to share the season.
Baden-Baden's forum is candid that September weather here is genuinely unpredictable — bright 25°C sunshine one stretch, rain and below 10°C the next, with no single year a reliable guide to the next. Regulars' standard advice is to pack layers and rain protection regardless of forecast, since the region rarely holds one pattern for more than a couple of days.
Other months in Heidelberg
Germany's forum calls June genuinely variable — anywhere from hot and humid around 30-35°C to chilly and rainy at 15-20°C in the same month. Regulars' standard packing list covers both: summer clothes plus a hooded rain jacket and a warm sweater, since Heidelberg's Neckar valley runs a touch milder than much of the rest of the country but not immune to the swings.
Add your own note from Heidelberg's card on the map.
Heidelberg climate normals — September
| Daytime high | 23°C / 74°F | 😎 nice |
|---|---|---|
| Nighttime low | 12°C / 53°F | |
| Feels like (high) | 22°C / 72°F | |
| Rainfall | 75 mm / 3 in | 🌦 some rain |
| Rainy days | 10 days | |
| Humidity | 71% | 💧 humid |
| Dew point | 11°C / 52°F | |
| Sunshine | 8.9 h/day | |
| Daylight | 12.6 h | |
| Wind | 13 km/h / 8 mph | |
| Air quality (US AQI) | 44 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Heidelberg 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.
Peak crowdsSeptember castle illumination, Heidelberger Herbst, school holidays in 3 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Heidelberg'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).
Best weatherHeidelberg's best weather comes in June, August and September — separate windows, not one continuous season.
September includes September castle illumination.
Best weatherFair weatherToughest weather
What's on in Heidelberg in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Festival
September castle illumination
5 SepMajor festivalCrowdedThe third and last illumination of the year, on the first Saturday of September, with a beer garden and live music on the Nepomuk terrace at the end of the old bridge from late afternoon. Source ↗
- Festival
Heidelberger Herbst
26–27 SepMajor festivalCrowdedThe old town becomes a street fair and flea market for a weekend at the end of September, with stages in the squares and the Hauptstrasse shoulder to shoulder from noon. Source ↗
Nearby, and something's on
Within 300 km of Heidelberg — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Heidelberg?
Heidelberg in September — FAQ
- Is September a good time to visit Heidelberg?
- September in Heidelberg: nice, a little rain, with clean air — one of the best months to visit. It ranks #1 of 12 months for Heidelberg on SeasonMap's comfort score (91/100).
- What is the weather like in Heidelberg in September?
- In September, Heidelberg averages a daily high of 23.1°C and a low of 11.8°C, with about 75 mm of rain over roughly 9.8 rainy days.
- What is the air quality in Heidelberg in September?
- Heidelberg has a mean US Air Quality Index of about 44 in September.
Other months in Heidelberg
Compare Heidelberg in September
Warmer or cooler than Heidelberg in September
Similar destinations in Central Europe — September
Within 300 km: Strasbourg's Cathedral summer light show around 1 Jul – 5 Sep, and Luxembourg's Schueberfouer on 21 Aug – 9 Sep.