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Prague · September · relief from the heat

Coolest places to go from Prague in September

In September, the coolest well-known place within 15 hours of Prague is Reykjavik, Iceland, 10.2 °C cooler than Prague and 6.3 h sun a day, about 7h each way by air. Without flying, it is La Chaux-de-Fonds, Switzerland, 3.6 °C cooler than Prague, about 11h 24m each way by train, for about 35× less carbon (19.2 kg CO₂e return against 663 kg).

The 10 coolest places within 15 hours of Prague

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.

  1. Reykjavik, Iceland10.2 °C cooler · 6.3 h sun a day · 3.5 mm rain a day · sea 10.8 °Cair ≈ 7h · 663 kg CO₂e return
  2. Tromsø, Norway8.0 °C cooler · 4.9 h sun a day · 5.2 mm rain a dayair ≈ 6h 24m · 550 kg CO₂e return
  3. Östersund, Sweden7.0 °C cooler · 7.7 h sun a day · 2.6 mm rain a dayair ≈ 5h 24m · 366 kg CO₂e return
  4. Bodø, Norway6.8 °C cooler · 5.2 h sun a day · 6.6 mm rain a day · sea 13.0 °Cair ≈ 6h · 481 kg CO₂e return
  5. Rovaniemi, Finland6.5 °C cooler · 6.0 h sun a day · 3.5 mm rain a dayair ≈ 6h 6m · 486 kg CO₂e return
  6. Trondheim, Norway5.9 °C cooler · 7.0 h sun a day · 5.8 mm rain a dayair ≈ 5h 30m · 378 kg CO₂e return
  7. Sundsvall, Sweden5.4 °C cooler · 8.4 h sun a day · 2.3 mm rain a day · sea 14.2 °Cair ≈ 5h 18m · 347 kg CO₂e return
  8. Luleå, Sweden5.4 °C cooler · 7.7 h sun a day · 2.4 mm rain a day · sea 14.3 °Cair ≈ 5h 54m · 448 kg CO₂e return
  9. Dundee, United Kingdom5.3 °C cooler · 7.7 h sun a day · 2.0 mm rain a day · sea 13.9 °Cair ≈ 5h 18m · 340 kg CO₂e return
  10. Glasgow, United Kingdom4.7 °C cooler · 7.2 h sun a day · 3.4 mm rain a dayair ≈ 5h 24m · 352 kg CO₂e return

Without flying

The coolest places the train reaches within 15 hours. La Chaux-de-Fonds is 3.6 °C cooler for 19.2 kg — about 35× less carbon than flying to Reykjavik.

  1. La Chaux-de-Fonds, Switzerland3.6 °C cooler · 9.2 h sun a day · 3.5 mm rain a dayrail ≈ 11h 24m · 19.2 kg CO₂e return
  2. Zakopane, Poland3.2 °C cooler · 8.8 h sun a day · 3.9 mm rain a dayrail ≈ 7h 54m · 12.0 kg CO₂e return
  3. Jönköping, Sweden3.1 °C cooler · 8.9 h sun a day · 1.9 mm rain a dayrail ≈ 14h 24m · 25.2 kg CO₂e return
  4. Gothenburg, Sweden2.7 °C cooler · 9.0 h sun a day · 3.2 mm rain a day · sea 17.2 °Crail ≈ 14h 30m · 25.4 kg CO₂e return
  5. Memmingen, Germany2.7 °C cooler · 9.6 h sun a day · 3.5 mm rain a dayrail ≈ 7h 36m · 11.4 kg CO₂e return
  6. Herning, Denmark2.6 °C cooler · 8.8 h sun a day · 2.7 mm rain a dayrail ≈ 13h · 22.5 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 Prague in September within 15 hours is Reykjavik, 10.2 °C cooler, costing 663 kg CO₂e return. The lowest-carbon option is Hof at 5.3 kg — 125× less carbon, for 7.6 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.

HofReykjavik
Where they are. Solid lines are rail or ferry, dashed are flights, from Prague. Pick one to compare.
Carbon against relief from the heat, September, departing Prague. Journeys of up to 15 hours each way.7 destinations. Lowest carbon Hof at 5.3 kilograms and 2.6 °C cooler; best for relief from the heat Reykjavik at 663 kilograms and 10.2 °C cooler. Hof · 5.3 kgLa Chaux-de-Fonds · 19.2 kgOslo · 281 kgReykjavik · 663 kg

By rail or ferry By air

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

What the 15-hour limit costs: at this budget Lillehammer can only be reached by air — 315 kg CO₂e, in 5h 12m. Allow up to 24 hours and the train does the same journey for 36.9 kg in 20h 6m — 9× less carbon for 14h 54m more travelling.

September from Prague — 7 destinations on the frontier, 2 without flying.
DestinationHowCO₂e returnTempSun/dayRain/dayJourney
Hof, GermanyRail5.3 kg15.1 °C9.5 h2.1 mm4h 36m
La Chaux-de-Fonds, SwitzerlandRail19.2 kg14.1 °C9.2 h3.5 mm11h 24m
Oslo, NorwayAir281 kg13.3 °C7.3 h3.4 mm5h
Lillehammer, NorwayAir315 kg12.0 °C7.0 h4.6 mm5h 12m
Östersund, SwedenAir366 kg10.7 °C7.7 h2.6 mm5h 24m
Tromsø, NorwayAir550 kg9.7 °C4.9 h5.2 mm6h 24m
Reykjavik, IcelandAir663 kg7.5 °C6.3 h3.5 mm7h

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 La Chaux-de-Fonds (19.2 kg, 3.6 °C cooler) to Oslo (281 kg, 4.4 °C cooler) buys 0.8 °C more relief from the heat for an extra 262 kg — 327 kg of CO₂e per degree. That single step is the most expensive relief from the heat on the whole curve.

The pick of them

Hof, GermanyHofGermany5.3 kg CO₂e return15.1 °C · 9.5 h sun · 4h 36m by railwarm overallLa Chaux-de-FondsSwitzerland19.2 kg CO₂e return14.1 °C · 9.2 h sun · 11h 24m by railmild and brightReykjavik, IcelandReykjavikIceland663 kg CO₂e return7.5 °C · 6.3 h sun · 7h 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 Prague

September from elsewhere

Photo credits

Questions

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

Reykjavik, Iceland, at 10.2 °C cooler. Reaching it emits 663 kg CO₂e return, travelling 7h each way by air (modelled).

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

Yes. La Chaux-de-Fonds reaches 3.6 °C cooler and is reachable by rail or ferry in 11h 24m (modelled), emitting 19.2 kg CO₂e return — though Reykjavik is cooler still, if you fly.

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

663 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.