A heatwave in Wales arrives at a lower temperature than most visitors expect. For most of the country, the Met Office counts a heatwave once daytime highs reach 25°C for three days in a row, a threshold well below the 28°C used in the hottest parts of England.
This guide explains what a Welsh heatwave actually looks like, how hot it really gets, the national record, and how to plan a summer trip around the heat.
If a warm spell has you thinking about a Welsh city break, you can compare flights to Cardiff, browse hotels in Cardiff, or look across the wider United Kingdom. This piece sits alongside our broader coverage of the UK heatwave 2026 and the Europe heatwave 2026.
As of 29 July 2026, Wales is not under any heat warning, even as parts of England sit under an amber heat-health alert. Wales has already had three separate heatwaves this year, in May, June and early July, with the June spell setting a new national record.
The bigger Welsh weather story right now is dryness rather than heat: drought has been declared across North Wales and the Upper Severn, and wildfires have burned in parts of the country for more than a week. More on both below.
What counts as a heatwave in Wales?
A UK heatwave needs at least three consecutive days on which the daily maximum temperature meets or exceeds a set threshold, as defined by the Met Office. That threshold is not the same everywhere, since it is calculated from each area’s own summer climate, so cooler regions have a lower bar.
For most of Wales, the threshold is 25°C, the same level used across Scotland, Northern Ireland, much of northern England and south-west England. It sits below the 26°C to 28°C range that applies across central and south-east England.
Why the Welsh bar is lower
The thresholds reflect what is genuinely unusual for a place, based on the 1991 to 2020 climate averages measured around the middle of summer. A run of 25°C days is far more of an outlier in Gwynedd than in Surrey, so it registers as a heatwave in one and not the other.
The practical takeaway for a visitor: a Welsh heatwave is real heat by local standards, and the country is built for cool, damp weather rather than hot spells. That mismatch is what makes the heat feel stronger than the number suggests.
How hot does Wales actually get?
Wales’s all-time temperature record is 37.1°C, recorded at Hawarden Airport in Flintshire on 18 July 2022, verified by the Met Office after the extreme heat event that pushed England past 40°C for the first time. The reading beat the previous Welsh record of 35.2°C, set in the same Flintshire village back in August 1990.
Warm summer days in Wales more often top out in the high teens to low 20s Celsius. Genuinely hot days in the high 20s or low 30s are uncommon, tend to be short-lived, and usually favour inland and eastern Wales, including the Cardiff area and the Wye and Dee valleys, over the cooler coast and the higher ground of Eryri (Snowdonia) and the Cambrian Mountains.
Where Wales is hottest
Heat concentrates away from the sea, with sheltered inland valleys and the lower-lying southeast warming up fastest. Sea breezes keep the coast a few degrees cooler and the uplands cooler still.
This is why the national record sits in Flintshire in the northeast, close to the English border, rather than on the Atlantic-facing west coast.
The 2026 heatwave timeline
2026 has been Wales’s most heatwave-heavy year on record, with three separate spells verified by the Met Office by late July. Cardiff’s Bute Park has been the focal point for nearly every reading.
| Heatwave | Dates | Peak at Bute Park, Cardiff | Note |
|---|---|---|---|
| May 2026 | 22–31 May | 32.9°C (26 May) | Part of the UK’s warmest May on record |
| June 2026 | 19–28 June | 35.9°C (25 June) | New Welsh June record, plus a new June overnight record of 23.5°C |
| July 2026 | 4–26 July | 31.3°C (9 July) | Cooler than June at Bute Park; nationally the UK saw 35°C+ readings in three separate months for the first time on record |
As of 29 July, Wales sits between spells: warm in the southeast today, reaching around 25°C, but turning fresher from Thursday with highs back in the low-to-mid 20s and no heat warnings in force. England, by contrast, has been under an amber heat-health alert for a fresh heatwave over the same period.
Drought and wildfires: the bigger story this summer
Dryness, not just heat, has defined Wales’s summer in 2026. On 23 July, Natural Resources Wales declared drought status for North Gwynedd, Ynys Môn, South Gwynedd, the Dee catchment, Clwyd and the Upper Severn, with the rest of the country classed as being in prolonged dry weather.
Those drought-hit catchments received less than 2% of their expected July rainfall, and July 2026 was on course to be the driest month in Wales for almost 190 years. Several areas of North Wales had seen no significant rain since 6 July.
Wildfires and travel advice
Wildfires burned across North and South East Wales for more than a week through late July, prompting the Welsh Government to activate crisis response plans amid a shortage of firefighting helicopters. Natural Resources Wales and the Wales Wildfire Board warn that dry grass and mountainsides can catch from a single spark and spread within minutes.
Most wildfires in Wales are started by people rather than by natural causes. In 2025, fire services across Wales attended 3,474 grass fire incidents, and the great majority were started deliberately.
The official #WildfireWise advice for visitors and residents is simple:
- Do not light campfires or barbecues in the countryside during dry weather.
- Never discard cigarettes or glass.
- Take all litter home.
- Report it if you see someone starting fires.
Low river levels and dry ground also raise the risk of disruption to outdoor attractions and water-based activities, so check conditions locally before a trip into rural or upland Wales.
Cardiff and Swansea in the heat
Wales’s two largest cities feel hot spells acutely because they are dense, built of heat-holding stone and brick, and short on shade and air conditioning.
Cardiff
Cardiff is where Welsh heat records tend to fall, as the June 2026 spell showed at Bute Park in the city centre. The compact core around the castle, the civic centre and Cardiff Bay traps warmth through the afternoon and releases it slowly after dark, so nights can stay uncomfortable.
If you are visiting in a warm spell, hotels in Cardiff with good ventilation or cooling are worth prioritising.
Swansea
Swansea, on Swansea Bay to the west, usually runs a touch cooler than Cardiff thanks to its seafront position and the breeze off the water. It still warms up in a heatwave, and nearby Gower beaches draw large crowds on hot days.
The coast tempers the peak, so the city tends to avoid the very highest inland readings.
Why Welsh homes struggle in the heat
Wales, like the rest of the UK, is built for cold, and that works against residents once the heat arrives. Only about 5% of British homes have air conditioning, and Welsh housing stock is designed to hold heat in through long, cool, damp winters.
Indoor heat build-up
Because buildings retain warmth, indoor temperatures build up over several days of hot weather and stay high overnight. British Red Cross research has found that around half of UK homes overheat in summer, and top-floor flats fare worst.
Most people rely on fans, open windows and passive cooling rather than air conditioning.
How to stay safe and cool
The groups most at risk in a Welsh heatwave are older people, babies and young children, and anyone with a long-term health condition, along with people who work or exercise outdoors, per Public Health Wales guidance.
The core advice for staying cool:
- Keep your space cool. Close curtains and windows on the sunny side during the day, and open them at night when the air is cooler.
- Stay out of the midday sun. Do errands, exercise or sightseeing in the early morning or evening rather than the hottest hours.
- Drink plenty of water and go easy on alcohol and caffeine.
- Dress for it. Wear loose, light clothing, and use SPF 30+ sunscreen with at least 4-star UVA protection.
- Check on others. Look in on older neighbours, relatives and anyone living alone.
- Never leave people or pets in parked cars, and do not cover a pram or buggy with a cloth, which traps heat.
Public Health Wales also warns against cooling off in open water, since reservoirs, rivers and the sea can trigger cold-water shock even on the hottest days. If you do swim, enter slowly, stay near the shore, and never swim in reservoirs.
If someone feels unwell, move them to a cool place, get them to rest and drink water. Suspected heatstroke, marked by confusion, a very high temperature or loss of consciousness, is a medical emergency: call 999.
When to go and booking tips
The warmest and driest stretch in Wales typically runs from June to August, when average Cardiff highs sit around 19°C to 20°C and long daylight hours make the most of the scenery. Genuine heatwaves are usually the exception rather than the rule, though 2026 has been an unusually heatwave-heavy year, so pack layers and a rain jacket whatever the forecast says.
If you want the heat, aim for July and inland or southeastern Wales. If you prefer milder conditions, the coast, the far west and the uplands stay cooler, and late spring or early autumn are quieter and gentler on the thermometer.
Getting there
Cardiff Airport (CWL) is the main gateway into Wales. Ryanair runs a summer 2026 schedule from Cardiff to sun destinations including Alicante, Faro, Malaga and Tenerife, plus Dublin, and other carriers add further links.
Many international travellers also route through London or Manchester and continue by train, so it is worth comparing flights to the United Kingdom as a whole. Full-service options such as British Airways connect the UK’s larger hubs.
Where to stay
For a heat-season trip, book early and choose rooms with good airflow or cooling, especially in the cities. Compare hotels in Cardiff for a base near the capital’s sights, or browse hotels across the United Kingdom if you are combining Wales with stops in England or Scotland.
Frequently Asked Questions
What is the hottest temperature ever recorded in Wales?
37.1°C, at Hawarden Airport in Flintshire on 18 July 2022, verified by the Met Office. It beat the previous Welsh record of 35.2°C from August 1990, and no new all-time record has been set in 2026.
What counts as a heatwave in Wales?
Three or more consecutive days with daytime highs of at least 25°C, the Met Office threshold for most of Wales.
Is Wales in a heatwave right now?
No, as of 29 July 2026 there is no heat warning in force for Wales, even as England sits under one. Wales has had three heatwaves already this year, in May, June and early July, with the June spell setting a new national record of 35.9°C at Bute Park in Cardiff on 25 June.
Which part of Wales is hottest?
Inland and eastern Wales, including the Cardiff area and the valleys near the English border. The coast and the uplands of Eryri (Snowdonia) and the Cambrian Mountains stay cooler.
Is there a drought in Wales in 2026?
Yes. Natural Resources Wales declared drought status for North Gwynedd, Ynys Môn, South Gwynedd, the Dee catchment, Clwyd and the Upper Severn on 23 July 2026, with the rest of the country classed as being in prolonged dry weather.
Sources
- Met Office: Record high temperatures verified
- Met Office: What is a heatwave
- Met Office: June 2026 heatwave, a recap of the temperature records
- Met Office: Prolonged spell of hot weather continues into next week
- Met Office: Wales regional weather forecast
- Natural Resources Wales: Wildfires and record dry conditions trigger drought declaration for North Wales and Upper Severn
- ITV News Wales: Drought status for North Wales and Upper Severn after record dry conditions
- Public Health Wales: Extreme hot weather
- British Red Cross: Why UK heat feels so bad
- timeanddate: Climate and weather averages in Cardiff
- Routes: Ryanair launches summer 2026 schedule at Cardiff Airport
Disclaimer: Wego strives to ensure all information presented in this article is accurate and up to date at the time of publication. Travel policies, prices, visa requirements, and conditions can change rapidly. We strongly recommend verifying critical details with official sources before making travel decisions. Wego does not accept liability for any inaccuracies, oversights, or changes that may occur after publication.
