Frankfurt · September · relief from the heat

Coolest places to go from Frankfurt in September

In September, the coolest well-known place within 15 hours of Frankfurt is Reykjavik, Iceland, 10.1 °C cooler than Frankfurt and 6.3 h sun a day, about 6h 42m each way by air. Without flying, it is Glasgow, United Kingdom, 4.6 °C cooler than Frankfurt, about 14h 12m each way by train, for about 9× less carbon (63.5 kg CO₂e return against 597 kg).

The 10 coolest places within 15 hours of Frankfurt

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, Iceland10.1 °C cooler · 6.3 h sun a day · 3.5 mm rain a day · sea 10.8 °Cair ≈ 6h 42m · 597 kg CO₂e return
Tromsø, Norway7.9 °C cooler · 4.9 h sun a day · 5.2 mm rain a dayair ≈ 6h 30m · 563 kg CO₂e return
Östersund, Sweden6.9 °C cooler · 7.7 h sun a day · 2.6 mm rain a dayair ≈ 5h 30m · 376 kg CO₂e return
Bodø, Norway6.7 °C cooler · 5.2 h sun a day · 6.6 mm rain a day · sea 13.0 °Cair ≈ 6h 6m · 487 kg CO₂e return
Rovaniemi, Finland6.4 °C cooler · 6.0 h sun a day · 3.5 mm rain a dayair ≈ 6h 12m · 518 kg CO₂e return
Trondheim, Norway5.8 °C cooler · 7.0 h sun a day · 5.8 mm rain a dayair ≈ 5h 30m · 373 kg CO₂e return
Sundsvall, Sweden5.3 °C cooler · 8.4 h sun a day · 2.3 mm rain a day · sea 14.2 °Cair ≈ 5h 24m · 368 kg CO₂e return
Luleå, Sweden5.3 °C cooler · 7.7 h sun a day · 2.4 mm rain a day · sea 14.3 °Cair ≈ 6h · 475 kg CO₂e return
Dundee, United Kingdom5.2 °C cooler · 7.7 h sun a day · 2.0 mm rain a day · sea 13.9 °Cair ≈ 4h 54m · 263 kg CO₂e return
Glasgow, United Kingdom4.6 °C cooler · 7.2 h sun a day · 3.4 mm rain a dayrail ≈ 14h 12m · 63.5 kg CO₂e return

Without flying

The coolest places the train reaches within 15 hours. Glasgow is 4.6 °C cooler for 63.5 kg — about 9× less carbon than flying to Reykjavik.

Glasgow, United Kingdom4.6 °C cooler · 7.2 h sun a day · 3.4 mm rain a dayrail ≈ 14h 12m · 63.5 kg CO₂e return
Dumfries, United Kingdom4.5 °C cooler · 7.4 h sun a day · 3.6 mm rain a day · sea 16.1 °Crail ≈ 14h 42m · 55.7 kg CO₂e return
Edinburgh, United Kingdom4.4 °C cooler · 7.4 h sun a day · 2.8 mm rain a day · sea 14.0 °Crail ≈ 14h · 61.7 kg CO₂e return
Oldham, United Kingdom4.0 °C cooler · 6.8 h sun a day · 4.6 mm rain a dayrail ≈ 11h 48m · 40.0 kg CO₂e return
La Chaux-de-Fonds, Switzerland3.5 °C cooler · 9.2 h sun a day · 3.5 mm rain a dayrail ≈ 6h 6m · 10.7 kg CO₂e return
Kristiansand, Norway3.3 °C cooler · 8.2 h sun a day · 4.7 mm rain a day · sea 16.4 °Crail ≈ 13h 48m · 26.4 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 Frankfurt in September within 15 hours is Reykjavik, 10.1 °C cooler, costing 597 kg CO₂e return. The lowest-carbon option is Ilmenau at 5.0 kg — 119× less carbon, for 7.8 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 Frankfurt. Pick one to compare.

By rail or ferry By air

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

What the 15-hour limit costs: at this budget Östersund can only be reached by air — 376 kg CO₂e, in 5h 30m. Allow up to 24 hours and the train does the same journey for 44.1 kg in 22h 6m — 9× less carbon for 16h 36m more travelling.

September from Frankfurt — 8 destinations on the frontier, 4 without flying.
Destination	How	CO₂e return	Temp	Sun/day	Rain/day	Journey
Ilmenau, Germany	Rail	5.0 kg	15.3 °C	9.8 h	2.1 mm	4h
Kempten (Allgaeu), Germany	Rail	8.6 kg	14.4 °C	9.2 h	4.0 mm	5h 30m
Buxton, United Kingdom	Rail	37.2 kg	12.8 °C	7.1 h	3.9 mm	12h 24m
Bathgate, United Kingdom	Rail	62.3 kg	12.5 °C	7.2 h	3.0 mm	15h
Kristiansund, Norway	Air	364 kg	11.6 °C	7.1 h	6.5 mm	5h 24m
Östersund, Sweden	Air	376 kg	10.7 °C	7.7 h	2.6 mm	5h 30m
Tromsø, Norway	Air	563 kg	9.7 °C	4.9 h	5.2 mm	6h 30m
Reykjavik, Iceland	Air	597 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 Bathgate (62.3 kg, 5.1 °C cooler) to Kristiansund (364 kg, 6.0 °C cooler) buys 0.9 °C more relief from the heat for an extra 301 kg — 335 kg of CO₂e per degree. That single step is the most expensive relief from the heat on the whole curve.

The pick of them

IlmenauGermany5.0 kg CO₂e return15.3 °C · 9.8 h sun · 4h by railwarm overall

BathgateUnited Kingdom62.3 kg CO₂e return12.5 °C · 7.2 h sun · 15h by railmild and bright

ReykjavikIceland597 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 Frankfurt

September from elsewhere

Photo credits

Bathgate: Richard Webb, CC BY-SA 2.0, 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
Dumfries: cisko66, CC BY 3.0, via Wikimedia Commons
Edinburgh: 瑞丽江的河水, CC BY-SA 4.0, via Wikimedia Commons
Oldham: Matt from Oldham, UK, CC BY 2.0, via Wikimedia Commons
Kristiansand: unknown author, CC BY 2.5, via Wikimedia Commons

Questions

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

Reykjavik, Iceland, at 10.1 °C cooler. Reaching it emits 597 kg CO₂e return, travelling 6h 42m each way by air (modelled).

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

Yes. Bathgate reaches 5.1 °C cooler and is reachable by rail or ferry in 15h (modelled), emitting 62.3 kg CO₂e return — though Reykjavik is cooler still, if you fly.

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

597 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.