Temperatures may hit an all-time record on Wednesday and Thursday, according to Met Éireann.
The national forecaster said it was watching closely as the current heatwave continued and warnings have been issued for temperatures in the region of 30 degrees.
Tuesday Met Éireann issued the country’s first orange alert for high temperatures. This applied to counties Cavan, Monaghan, south Leitrim, Roscommon, Longford and Westmeath, while a status yellow heat warning has been applied countrywide for the week.
Temperatures reached their highest on Tuesday in Mount Dillon, Co Roscommon, at 29.5 degrees.
The highest temperature ever recorded in Ireland was 33.3 degrees at Kilkenny Castle, on June 26th, 1887. The highest ever recorded in the 20th century was 32.5 degrees at Boora Co Offaly on June 29th, 1976.
An analysis of the peak temperatures for every decade since the 1940s shows peaks between 29.8 degrees in the 1950s to 32.3 in the 2000s.
In comparison, the Republic's recent high was just 29.6 degrees at Durrow, Co Laois, on Saturday. The same day temperatures in Northern Ireland reached 31.2 degrees at Ballywatticock, Co Down.
But Met Éireann said while there are hot days peaking with temperatures in the mid to high 20s, “heatwaves” such as the current conditions, were less common and occur more infrequently in Ireland than the rest of Europe.
Met Éireann defined a heatwave as five consecutive days with a maximum temperature in excess of 25 degrees. It said heatwaves occur when high pressure systems, also known as anticyclones, persist for a prolonged period of time, resulting in dry and settled weather.
Meteorologist Bonnie Diamond of Met Éireann said a tropical Continental air mass, is expected to maintain high temperatures over the coming days, prompting health and safety warnings.
Because Ireland only experiences occasional heatwaves compared to other European countries, those that do come our way are notable.
In August 1976, Birr, Co Offaly recorded heat wave conditions lasting 14 days. The maximum temperature recorded at that station during this event was 28.2 degrees which was 8.9 degrees above its long-term average.
More recently, heatwave conditions occurred in the summers of 2018, 2017, 2013, 2006, 2003, 1995, 1989 and 1983.
In the summer of 2018, Ireland experienced a similar prolonged spell of hot, sunny weather associated with similar conditions, which that year led to absolute drought conditions. An absolute drought is a period of 15 or more consecutive days with daily rainfall of less than 0.2mm.
Met Éireann said the current dry spell may break over the weekend with Friday bringing a mix of warm sunny spells and scattered showers.
Following Met Éireann’s warning, the State’s chief medical officer Dr Tony Holohan said people should get outdoors this week to reduce exposure to Covid-19, but also to enjoy the weather.
However, he warned it was “ important to do so in as safe a way as possible”.
Dr Holohan said people should “regularly and liberally apply sunscreen that has a sun protection factor of at least 30 plus for adults and 50 plus for children, wear light and loose-fitting clothing that covers your skin, wear a hat and sunglasses. Keep yourself cool and hydrated.”
Other risks to be mindful of during this spell of hot weather are heat exhaustion.
The Health Service Executive said heatwaves can cause “significant increases in mortality” especially in older people, young children and more vulnerable groups.