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Barcelona · May · relief from the heat

Coolest places to go from Barcelona in May

The coolest place you can reach from Barcelona in May within 15 hours is Reykjavik, 10.6 °C cooler, costing 745 kg CO₂e return. The lowest-carbon option is Castres at 7.3 kg — 102× less carbon, for 7.9 degrees less relief from the heat.

The 10 coolest places within 15 hours of Barcelona

Ranked on relief from the heat in May 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. Tromsø, Norway11.3 °C cooler · 7.0 h sun a dayair 7h 54m · 827 kg CO₂e return
  2. Reykjavik, Iceland10.6 °C cooler · 6.4 h sun a dayair 7h 30m · 745 kg CO₂e return
  3. Rovaniemi, Finland9.4 °C cooler · 13.4 h sun a dayair 7h 42m · 791 kg CO₂e return
  4. Luleå, Sweden9.3 °C cooler · 14.8 h sun a dayair 7h 30m · 746 kg CO₂e return
  5. Bodø, Norway8.9 °C cooler · 9.4 h sun a dayair 7h 30m · 748 kg CO₂e return
  6. Oulu, Finland8.9 °C cooler · 14.4 h sun a dayair 7h 30m · 758 kg CO₂e return
  7. Umeå, Sweden8.2 °C cooler · 15.0 h sun a dayair 7h 12m · 693 kg CO₂e return
  8. Erzurum, Turkey7.7 °C cooler · 10.8 h sun a dayair 7h 54m · 824 kg CO₂e return
  9. Kars, Turkey7.7 °C cooler · 10.5 h sun a dayair 8h · 856 kg CO₂e return
  10. Vaasa, Finland7.4 °C cooler · 14.8 h sun a dayair 7h 6m · 686 kg CO₂e return

Without flying

The coolest places the train reaches within 15 hours. La Chaux-de-Fonds is 6.4 °C cooler for 21.7 kg — about 38× less carbon than flying to Tromsø.

  1. La Chaux-de-Fonds, Switzerland6.4 °C cooler · 9.6 h sun a dayrail 10h 42m · 21.7 kg CO₂e return
  2. Memmingen, Germany4.7 °C cooler · 9.1 h sun a dayrail 14h 24m · 28.6 kg CO₂e return
  3. Ávila, Spain4.7 °C cooler · 12.6 h sun a dayrail 5h 54m · 17.1 kg CO₂e return
  4. Canterbury, United Kingdom4.5 °C cooler · 11.6 h sun a dayrail 14h 42m · 40.6 kg CO₂e return
  5. Milton Keynes, United Kingdom4.4 °C cooler · 9.7 h sun a dayrail 14h 24m · 39.5 kg CO₂e return
  6. Oxford, United Kingdom4.1 °C cooler · 10.4 h sun a dayrail 14h 36m · 40.2 kg CO₂e return

Rail times are modelled; air times include getting to and through the airport.

The low-carbon trade-off

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

CastresReykjavik
Where they are. Solid lines are rail or ferry, dashed are flights, from Barcelona. Pick one to compare.
Carbon against relief from the heat, May, departing Barcelona. Journeys of up to 15 hours each way.7 destinations. Lowest carbon Castres at 7.3 kilograms and 2.7 °C cooler; best for relief from the heat Reykjavik at 745 kilograms and 10.6 °C cooler. Castres · 7.3 kgLa Chaux-de-Fonds · 21.7 kgÖstersund · 643 kgReykjavik · 745 kg

By rail or ferry By air

Carbon against relief from the heat, May, departing Barcelona. Journeys of up to 15 hours each way.
May from Barcelona — 7 destinations on the frontier, 3 without flying.
DestinationHowCO₂e returnTempSun/dayRain/dayJourney
Castres, FranceRail7.3 kg14.5 °C9.3 h5.1 mm5h 6m
Rodez, FranceRail9.8 kg12.2 °C9.6 h5.1 mm6h 12m
La Chaux-de-Fonds, SwitzerlandRail21.7 kg10.8 °C9.6 h4.8 mm10h 42m
Östersund, SwedenAir643 kg9.9 °C14.2 h0.7 mm6h 54m
Umeå, SwedenAir693 kg9.0 °C15.0 h0.6 mm7h 12m
Raahe, FinlandAir743 kg7.4 °C14.7 h1.0 mm7h 24m
Reykjavik, IcelandAir745 kg6.6 °C6.4 h5.9 mm7h 30m

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 (21.7 kg, 6.4 °C cooler) to Östersund (643 kg, 7.3 °C cooler) buys 0.9 °C more relief from the heat for an extra 621 kg — 690 kg of CO₂e per degree. That single step is the most expensive relief from the heat on the whole curve.

The pick of them

CastresFrance7.3 kg CO₂e return14.5 °C · 9.3 h sun · 5h 6m by railmild and brightLa Chaux-de-FondsSwitzerland21.7 kg CO₂e return10.8 °C · 9.6 h sun · 10h 42m by railmild and brightReykjavik, IcelandReykjavikIceland745 kg CO₂e return6.6 °C · 6.4 h sun · 7h 30m by aircool

The same month, asked differently

May 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 Barcelona

May from elsewhere

Photo credits

Questions

Where is the coolest place to go from Barcelona in May?

Reykjavik, Iceland, at 10.6 °C cooler. Reaching it emits 745 kg CO₂e return, travelling 7h 30m each way by air (modelled).

Can I get somewhere cool from Barcelona in May without flying?

Yes. La Chaux-de-Fonds reaches 6.4 °C cooler and is reachable by rail or ferry in 10h 42m (modelled), emitting 21.7 kg CO₂e return — though Reykjavik is cooler still, if you fly.

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

745 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.