Brussels · May · relief from the heat

Coolest places to go from Brussels in May

In May, the coolest well-known place within 15 hours of Brussels is Tromsø, Norway, 7.9 °C cooler than Brussels and 7.0 h sun a day, about 6h 30m each way by air. Without flying, it is Aberdeen, United Kingdom, 3.1 °C cooler than Brussels, about 12h 30m each way by train, for about 9× less carbon (60.9 kg CO₂e return against 560 kg).

The 10 coolest places within 15 hours of Brussels

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.

Tromsø, Norway7.9 °C cooler · 7.0 h sun a day · 4.9 mm rain a dayair ≈ 6h 30m · 560 kg CO₂e return
Reykjavik, Iceland7.2 °C cooler · 6.4 h sun a day · 5.9 mm rain a day · sea 7.5 °Cair ≈ 6h 18m · 535 kg CO₂e return
Rovaniemi, Finland6.0 °C cooler · 13.4 h sun a day · mostly dryair ≈ 6h 18m · 531 kg CO₂e return
Luleå, Sweden5.9 °C cooler · 14.8 h sun a day · mostly dry · sea 1.5 °Cair ≈ 6h 6m · 485 kg CO₂e return
Bodø, Norway5.5 °C cooler · 9.4 h sun a day · 4.4 mm rain a day · sea 6.4 °Cair ≈ 6h · 480 kg CO₂e return
Oulu, Finland5.5 °C cooler · 14.4 h sun a day · mostly dry · sea 2.2 °Cair ≈ 6h 12m · 500 kg CO₂e return
Umeå, Sweden4.8 °C cooler · 15.0 h sun a day · mostly dry · sea 3.8 °Cair ≈ 5h 48m · 433 kg CO₂e return
Erzurum, Turkey4.3 °C cooler · 10.8 h sun a day · 4.7 mm rain a dayair ≈ 7h 36m · 777 kg CO₂e return
Kars, Turkey4.3 °C cooler · 10.5 h sun a day · 4.1 mm rain a dayair ≈ 7h 42m · 798 kg CO₂e return
Vaasa, Finland4.0 °C cooler · 14.8 h sun a day · mostly dry · sea 5.2 °Cair ≈ 5h 48m · 429 kg CO₂e return

Without flying

The coolest places the train reaches within 15 hours. Aberdeen is 3.1 °C cooler for 60.9 kg — about 9× less carbon than flying to Tromsø.

Aberdeen, United Kingdom3.1 °C cooler · 9.5 h sun a day · 2.2 mm rain a day · sea 9.0 °Crail ≈ 12h 30m · 60.9 kg CO₂e return
La Chaux-de-Fonds, Switzerland3.0 °C cooler · 9.6 h sun a day · 4.8 mm rain a dayrail ≈ 8h 30m · 13.4 kg CO₂e return
Buxton, United Kingdom2.7 °C cooler · 10.4 h sun a day · 2.8 mm rain a dayrail ≈ 8h 18m · 27.9 kg CO₂e return
Dundee, United Kingdom2.5 °C cooler · 8.7 h sun a day · 2.2 mm rain a day · sea 10.0 °Crail ≈ 11h 18m · 56.3 kg CO₂e return
Scarborough, United Kingdom2.3 °C cooler · 10.9 h sun a day · 1.9 mm rain a day · sea 9.8 °Crail ≈ 8h 48m · 34.3 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 Brussels in May within 15 hours is Tromsø, 7.9 °C cooler, costing 560 kg CO₂e return. The lowest-carbon option is La Chaux-de-Fonds at 13.4 kg — 42× less carbon, for 4.9 degrees less relief from the heat.

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.

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

By rail or ferry By air

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

What the 15-hour limit costs: at this budget Östersund can only be reached by air — 378 kg CO₂e, in 5h 30m. Allow up to 24 hours and the train does the same journey for 44.3 kg in 23h 42m — 9× less carbon for 18h 12m more travelling.

May from Brussels — 6 destinations on the frontier, 1 without flying.
Destination	How	CO₂e return	Temp	Sun/day	Rain/day	Journey
La Chaux-de-Fonds, Switzerland	Rail	13.4 kg	10.8 °C	9.6 h	4.8 mm	8h 30m
Östersund, Sweden	Air	378 kg	9.9 °C	14.2 h	0.7 mm	5h 30m
Umeå, Sweden	Air	433 kg	9.0 °C	15.0 h	0.6 mm	5h 48m
Luleå, Sweden	Air	485 kg	7.9 °C	14.8 h	0.6 mm	6h 6m
Reykjavik, Iceland	Air	535 kg	6.6 °C	6.4 h	5.9 mm	6h 18m
Tromsø, Norway	Air	560 kg	5.9 °C	7.0 h	4.9 mm	6h 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 (13.4 kg, 3.0 °C cooler) to Östersund (378 kg, 3.9 °C cooler) buys 0.9 °C more relief from the heat for an extra 364 kg — 405 kg of CO₂e per degree. That single step is the most expensive relief from the heat on the whole curve.

The pick of them

La Chaux-de-FondsSwitzerland13.4 kg CO₂e return10.8 °C · 9.6 h sun · 8h 30m by railmild and bright

TromsøNorway560 kg CO₂e return5.9 °C · 7.0 h sun · 6h 30m by aircold but bright

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 Tromsø

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

Search places to stay in Tromsø →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 Brussels

May from elsewhere

Photo credits

Tromsø: Diego Delso, CC BY-SA 4.0, via Wikimedia Commons
Reykjavik: Hedwig Storch, CC BY-SA 3.0, via Wikimedia Commons
Luleå: Andreas Harnemo, CC BY-SA 3.0, via Wikimedia Commons
Bodø: Røed 20:41, 24 July 2006 (UTC), CC BY-SA 2.5, via Wikimedia Commons
Umeå: Jonipoon, CC BY-SA 4.0, via Wikimedia Commons
Kars: Bjørn Christian Tørrissen, CC BY-SA 3.0, via Wikimedia Commons
Aberdeen: Ragazzi00, CC BY-SA 3.0, via Wikimedia Commons
Buxton: Andrew Hill, CC BY-SA 2.0, 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
Scarborough: Thomas Tolkien, CC BY 2.0, via Wikimedia Commons

Questions

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

Tromsø, Norway, at 7.9 °C cooler. Reaching it emits 560 kg CO₂e return, travelling 6h 30m each way by air (modelled).

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

Yes. La Chaux-de-Fonds reaches 3.0 °C cooler and is reachable by rail or ferry in 8h 30m (modelled), emitting 13.4 kg CO₂e return — though Tromsø is cooler still, if you fly.

How much carbon does a return trip from Brussels to Tromsø produce?

560 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.