A high-pressure temperature warning has been issued for 12 counties as Ireland’s heatwave continues.

The warning includes Carlow, Kildare, Kilkenny, Laois, Longford, Meath, Offaly, Westmeath, Wexford, Limerick, Tipperary and Waterford, as the mercury hits the high 20s.

It will come into place at 1pm on Friday and will remain in place until 7am on Sunday.

While the weather gives us a much-needed dose of vitamin D, there are health concerns.

Brendan Kelly, professor of psychiatry at Trinity College Dublin, warned there is a downside for some people, particularly those suffering from mental illnesses or substance abuse.

‘For every one-degree Celsius rise in temperature, the rate of significant alcohol and drug misuse goes up by about 5 per cent. So, a one-degree Celsius rise in temperature is producing a noticeable increase in drug and alcohol misuse,’ he told RTÉ’s Morning Ireland.

He said rates of presentation for anxiety and depression also tend to rise by around 10 per cent during a heat wave as high temperatures lead to general irritability, poor sleep and increased alcohol misuse.

Prof. Kelly urged people to check in with vulnerable adults, including older people and those suffering from mental illnesses, who may not understand the impact of heat on their health.

However, he said the number-one piece of advice is to try to enjoy the weather while we can.

It comes as Met Éireann forecaster Deirdre Lowe confirmed that it will be a heatwave for parts of the country in the coming week, with temperatures remaining above 25C for five consecutive days.