Met Éireann issues heatwave advisory for Ireland with temperatures set to hit low 30s by Friday

Advisory and forecast

Met Éireann has issued a weather advisory from Wednesday 8 July until Tuesday 14 July, warning of heatwave conditions across the island of Ireland. Daytime maximum temperatures will widely exceed 25°C, with values climbing to the high 20s or even low 30s in places from Friday. The warmest conditions are expected in the south and east, where thermometers could reach 28°C on Tuesday and Wednesday before the hotter continental air mass arrives later in the week.

From Friday onwards, we'll be getting more of an easterly air flow and that's going to be feeding in the warmer continental air mass over the country.

Warm and humid nights are forecast, with minimum temperatures of 15°C or higher. Met Éireann has advised that tropical nights, when the temperature does not drop below 20°C, may occur in places this weekend. The UV index is expected to be high to very high throughout the period.

Impacts and warnings

The advisory highlights several potential impacts: water safety issues due to increased use of waterways, lakes and beaches; heat stress and dehydration, especially for the vulnerable and elderly; uncomfortable sleeping conditions; and possible disruption to public transport. Met Éireann also notes drought concerns and the potential for wildfires and forest fires as soils dry out.

The soils are expected to get drier, meaning that there is potential for water restrictions to be put in place.

There is also the chance of some thunderstorms later this week. Already this summer, nighttime water restrictions were imposed in parts of Cork due to warm weather and high demand.

Heatwave criteria

For the Republic of Ireland, a heatwave is defined as five consecutive days with temperatures above 25°C. Northern Ireland requires three consecutive days at or above 25°C. The current forecast suggests both thresholds could be met, which would mark the second heatwave of the summer, coming just two weeks after the previous one in which Northern Ireland recorded its hottest June day on record.

Continental heat dome

The hot spell is being driven by a heat dome over Europe that is pushing temperatures above 40°C on the continent. High pressure to the south is slowly moving northwards, drawing up a warm, humid tropical maritime air mass. By Friday, the high is expected to centre north of Ireland, feeding in the warmer continental air.

Public health advice

Met Éireann and the HSE have urged the public to be sun-smart and aware of the signs of heat exhaustion, which include excessive sweating, dizziness, headache, muscle cramps, nausea and fatigue. People are advised to close curtains during the day, drink water regularly, ventilate sleeping areas when the air is cooler, use light bedding, and check on those at increased risk.