Berlin · September · relief from the heat

Coolest places to go from Berlin in September

In September, the coolest well-known place within 15 hours of Berlin is Reykjavik, Iceland, 10.7 °C cooler than Berlin and 6.3 h sun a day, about 6h 42m each way by air. Without flying, it is Oslo, Norway, 4.9 °C cooler than Berlin, about 14h 6m each way by train, for about 24× less carbon (24.7 kg CO₂e return against 600 kg).

The 10 coolest places within 15 hours of Berlin

Ranked on relief from the heat in September alone, among well-known places (a Wikivoyage travel guide and at least 40,000 Wikipedia readers a year), one per area and at most three per country. The carbon is shown, not used to choose: the list further down is the other question, how much relief from the heat each extra kilogram buys.

Reykjavik, Iceland10.7 °C cooler · 6.3 h sun a day · 3.5 mm rain a day · sea 10.8 °Cair ≈ 6h 42m · 600 kg CO₂e return
Tromsø, Norway8.5 °C cooler · 4.9 h sun a day · 5.2 mm rain a dayair ≈ 6h 6m · 484 kg CO₂e return
Östersund, Sweden7.5 °C cooler · 7.7 h sun a day · 2.6 mm rain a dayair ≈ 5h 6m · 299 kg CO₂e return
Bodø, Norway7.3 °C cooler · 5.2 h sun a day · 6.6 mm rain a day · sea 13.0 °Cair ≈ 5h 42m · 413 kg CO₂e return
Rovaniemi, Finland7.0 °C cooler · 6.0 h sun a day · 3.5 mm rain a dayair ≈ 5h 48m · 426 kg CO₂e return
Trondheim, Norway6.4 °C cooler · 7.0 h sun a day · 5.8 mm rain a dayair ≈ 5h 6m · 308 kg CO₂e return
Sundsvall, Sweden5.9 °C cooler · 8.4 h sun a day · 2.3 mm rain a day · sea 14.2 °Cair ≈ 5h · 282 kg CO₂e return
Luleå, Sweden5.9 °C cooler · 7.7 h sun a day · 2.4 mm rain a day · sea 14.3 °Cair ≈ 5h 30m · 385 kg CO₂e return
Dundee, United Kingdom5.8 °C cooler · 7.7 h sun a day · 2.0 mm rain a day · sea 13.9 °Cair ≈ 5h · 287 kg CO₂e return
Glasgow, United Kingdom5.2 °C cooler · 7.2 h sun a day · 3.4 mm rain a dayair ≈ 5h 6m · 303 kg CO₂e return

Without flying

The coolest places the train reaches within 15 hours. Oslo is 4.9 °C cooler for 24.7 kg — about 24× less carbon than flying to Reykjavik.

Oslo, Norway4.9 °C cooler · 7.3 h sun a day · 3.4 mm rain a dayrail ≈ 14h 6m · 24.7 kg CO₂e return
Haugesund, Norway4.9 °C cooler · 7.8 h sun a day · 6.8 mm rain a day · sea 15.8 °Crail ≈ 14h 42m · 27.1 kg CO₂e return
Västerås, Sweden4.5 °C cooler · 8.2 h sun a day · 3.1 mm rain a dayrail ≈ 13h 42m · 24.0 kg CO₂e return
Stavanger, Norway4.5 °C cooler · 7.7 h sun a day · 6.6 mm rain a day · sea 15.8 °Crail ≈ 13h 48m · 25.4 kg CO₂e return
Uppsala, Sweden4.3 °C cooler · 8.0 h sun a day · 2.1 mm rain a dayrail ≈ 14h 24m · 25.3 kg CO₂e return
Tønsberg, Norway4.3 °C cooler · 7.8 h sun a day · 3.6 mm rain a day · sea 16.5 °Crail ≈ 13h 12m · 22.8 kg CO₂e return

≈ is the model's estimate (air times include getting to and through the airport); ✓ is a rail journey checked against a real timetable, with the date it was checked. Temperatures are historical daily means for 2023–2024, averaged across day and night, so afternoons run warmer.

The low-carbon trade-off

The coolest place you can reach from Berlin in September within 15 hours is Reykjavik, 10.7 °C cooler, costing 600 kg CO₂e return. The lowest-carbon option is Annaberg-Buchholz at 6.4 kg — 94× less carbon, for 7.0 degrees less relief from the heat.

Every destination here is on the efficiency frontier: nowhere else this site covers is both cooler in September and lower in carbon. Anything a better option beats outright has been left out.

Where they are. Solid lines are rail or ferry, dashed are flights, from Berlin. Pick one to compare.

By rail or ferry By air

Carbon against relief from the heat, September, departing Berlin. Journeys of up to 15 hours each way.

What the 15-hour limit costs: at this budget Östersund can only be reached by air — 299 kg CO₂e, in 5h 6m. Allow up to 24 hours and the train does the same journey for 35.0 kg in 19h 6m — 9× less carbon for 14h more travelling.

September from Berlin — 6 destinations on the frontier, 2 without flying.
Destination	How	CO₂e return	Temp	Sun/day	Rain/day	Journey
Annaberg-Buchholz, Germany	Rail	6.4 kg	14.5 °C	9.5 h	2.9 mm	4h 36m
Oslo, Norway	Rail	24.7 kg	13.3 °C	7.3 h	3.4 mm	14h 6m
Lillehammer, Norway	Air	244 kg	12.0 °C	7.0 h	4.6 mm	4h 48m
Östersund, Sweden	Air	299 kg	10.7 °C	7.7 h	2.6 mm	5h 6m
Tromsø, Norway	Air	484 kg	9.7 °C	4.9 h	5.2 mm	6h 6m
Reykjavik, Iceland	Air	600 kg	7.5 °C	6.3 h	3.5 mm	6h 42m

Warm is not the same as pleasant, which is why sunshine and rainfall are shown alongside temperature. All three are ERA5 monthly means for 2023–2024.

Where the curve breaks

The frontier is gentle until it isn't. Going from Östersund (299 kg, 7.5 °C cooler) to Tromsø (484 kg, 8.5 °C cooler) buys 1.0 °C more relief from the heat for an extra 186 kg — 186 kg of CO₂e per degree. That single step is the most expensive relief from the heat on the whole curve.

The pick of them

Annaberg-BuchholzGermany6.4 kg CO₂e return14.5 °C · 9.5 h sun · 4h 36m by railmild and bright

OsloNorway24.7 kg CO₂e return13.3 °C · 7.3 h sun · 14h 6m by railmild and bright

ReykjavikIceland600 kg CO₂e return7.5 °C · 6.3 h sun · 6h 42m by aircool

The same month, asked differently

September answers differently depending on what you are after, and the lists genuinely diverge: the brightest places are not the hottest, and in summer the useful question stops being where is warm at all.

Where to stay in Reykjavik

Places to stay in Reykjavik, Iceland, on a live map. Prices and availability come from Stay22 and its booking partners.

Search places to stay in Reykjavik →Opens the booking search in a new tab. Same partners as the map below.

Affiliate disclosure. A booking made through this map may earn 0xCarbon a commission, at no extra cost to you. It changes nothing above it: the emissions figures come from UK Government conversion factors and are computed before anyone is paid anything.See the method.

Other months from Berlin

September from elsewhere

Photo credits

Oslo: Jonipoon, CC BY-SA 3.0, via Wikimedia Commons
Reykjavik: Hedwig Storch, CC BY-SA 3.0, via Wikimedia Commons
Tromsø: Diego Delso, CC BY-SA 4.0, via Wikimedia Commons
Östersund: Lars Falkdalen Lindahl (User:Njaelkies Lea), CC BY-SA 3.0, via Wikimedia Commons
Bodø: Røed 20:41, 24 July 2006 (UTC), CC BY-SA 2.5, via Wikimedia Commons
Trondheim: Åge Hojem/Trondheim Havn from Trondheim, Norway, CC BY-SA 2.0, via Wikimedia Commons
Sundsvall: User:Ö1thpe0807 (image 1), User:I99limpan (image2), User:Larskallin (image3), Hans Lindqvist (image 4-5), Calle Eklund (, CC BY-SA 3.0, via Wikimedia Commons
Luleå: Andreas Harnemo, CC BY-SA 3.0, via Wikimedia Commons
Dundee: File:442 dundee header.png (Tay Bridge and RSS Discovery images):- Original: PlutosAcademy File:V&A Dundee Near Completi, CC BY-SA 4.0, via Wikimedia Commons
Glasgow: 瑞丽江的河水, CC BY-SA 4.0, via Wikimedia Commons
Haugesund: Efarestv, CC BY-SA 3.0, via Wikimedia Commons
Västerås: Einarspetz, CC BY-SA 4.0, via Wikimedia Commons
Stavanger: Original by en:User:Godztian, CC BY-SA 3.0, via Wikimedia Commons
Tønsberg: Copyright © Krg This photo was taken by Karl Ragnar Gjertsen. Please credit this photo Karl Ragnar Gjertsen in the immed, CC BY-SA 3.0, via Wikimedia Commons

Questions

Where is the coolest place to go from Berlin in September?

Reykjavik, Iceland, at 10.7 °C cooler. Reaching it emits 600 kg CO₂e return, travelling 6h 42m each way by air (modelled).

Can I get somewhere cool from Berlin in September without flying?

Yes. Oslo reaches 4.9 °C cooler and is reachable by rail or ferry in 14h 6m (modelled), emitting 24.7 kg CO₂e return — though Reykjavik is cooler still, if you fly.

How much carbon does a return trip from Berlin to Reykjavik produce?

600 kg CO₂e for one person, return, by air. That uses the UK Government's 2026 conversion factors, including radiative forcing for flights.

Carbon uses UK Government (DESNZ/DEFRA) 2026 conversion factors applied to great-circle distance, with radiative forcing included for flights. Rail journey times are modelled estimates, not timetabled services. Full method · download the data.