Ireland faces a status yellow high temperature warning until Friday, with Thursday expected to be the hottest day of the week as temperatures could reach 31C in parts of the country.
Met Éireann, the national meteorological service, has had the warning in place for every county in the Republic of Ireland since midday on Tuesday. It is due to expire at 9am on Friday. The alert covers a range of risks including water safety issues arising from increased use of lakes and beaches, uncomfortable sleeping conditions, heat stress and possible forest fires.
Mark Bowe, a meteorologist with the agency, said “very high” temperatures will continue. Wednesday was expected to see highs of around 27-28C and overnight lows above 15C, leaving warm and humid nights.
Looking to Thursday, Mr Bowe said: “That’s set to be the hottest day of the week. All that warm air will have fully arrived from Europe and temperatures are expected to be widespread over 25C – reaching around 30 or possibly 31C in parts of the Midlands and Connacht.” He also warned of a risk of some thunderstorms accompanying the heat.
Friday will bring a slight relief, with temperatures taking what Mr Bowe described as a “bit of a slide”. Showers will begin to move in, and the north west may experience heavy showers on Friday afternoon. The UK Met Office has forecast maximum temperatures of 24C in Northern Ireland on Wednesday, potentially rising to 27C on Thursday. The outlook into the weekend suggests showers or longer outbreaks of rain on Friday and Saturday, with the rain “perhaps heavy and thundery at times”.
Health risks and vulnerable groups
The heat warning is not merely a temperature forecast; it carries real consequences for public health. High temperatures can cause heat stress, with symptoms that include dizziness, headaches, nausea and confusion. The UK Health Security Agency (UKHSA), in partnership with the Met Office, operates a colour-coded Heat-Health Alert system (Green, Yellow, Amber, Red) to warn of potential health impacts. A Red alert signifies a significant risk to life for the general population. Vulnerable groups such as older people (especially those over 65), babies and young children, people with underlying health conditions or on certain medications, those living alone, outdoor workers and people experiencing homelessness are particularly at risk.
Public health advice stresses staying hydrated by drinking plenty of fluids (especially water), limiting alcohol and caffeine, keeping homes cool by closing curtains during the day and opening windows at night, and taking cool showers or using damp cloths. Strenuous activity should be avoided between 11am and 3pm, the hottest part of the day. Light-coloured, loose-fitting clothing, a wide-brimmed hat and sunglasses are recommended, along with sunscreen (SPF 30+ for adults, 50+ for children).
Water safety and cold water shock
An increase in people seeking to cool off in lakes, rivers and the sea brings heightened water safety concerns. The Royal Life Saving Society and other authorities have warned that even with air temperatures in the high 20s and low 30s, water bodies in the UK and Ireland can remain dangerously cold, often below 15C. This poses a risk of cold water shock, which can cause involuntary gasping, hyperventilation and panic. People are advised to use lifeguarded beaches, swim between the red and yellow flags, and be aware of hidden hazards in areas such as locks, marinas and harbours. Never leave children or pets in stationary vehicles, even for a short time.
Agriculture, wildlife and infrastructure
The agricultural sector is already counting the cost of heat stress. Economic losses in the UK are estimated at £205 million annually. Extreme heat and drought in the summer of 2025 are estimated to have cost arable farmers more than £800 million. Livestock suffer reduced productivity, fertility issues and increased welfare risks; dairy cows in particular can show decreased milk yield and quality.
Wildlife also faces serious threats. Natural water sources can dry up, food becomes scarce, and animals may become dehydrated and disoriented. Nocturnal animals have been observed active during the day, and birds and insects are especially vulnerable. Providing shallow dishes of water can help local wildlife cope.
Infrastructure is not immune either. Extreme heat can cause failures in heat-sensitive equipment, leading to power cuts and disruptions to water, energy and mobile phone services. Road surfaces can be damaged, and speed restrictions may be introduced on rail lines to prevent tracks from buckling.
Forest fires are another concern flagged by Met Éireann under the yellow warning. The dry conditions increase the risk of wildfires breaking out, particularly in areas of grassland or heath.
Broader European context and historical records
The current heatwave in Ireland and the UK is part of a wider European event. Some countries are experiencing temperatures up to 43-44C, and France has issued its highest level of heat alerts for many departments. The increased frequency and intensity of such heatwaves are directly linked to human-caused climate change; projections indicate that hot spells will become more common, particularly in the south-east of the UK.
Ireland’s highest recorded temperature remains a matter of historical debate. The figure of 33.3C at Kilkenny Castle on June 26, 1887 is sometimes cited but its accuracy is disputed. More reliably, 33.0C was recorded at Phoenix Park in Dublin on July 18, 2022, making that the highest temperature in the 21st century and the highest ever recorded in the capital. Six of Ireland’s ten warmest years have occurred since 1990. In the UK, the all-time record is 40.3C at Coningsby in Lincolnshire on July 19, 2022 – the first time 40C was recorded in the country, with 46 stations exceeding the previous UK record of 38.7C.
