Monday could be the hottest day of the year to date with temperatures reaching 27 degrees in eastern parts of the country.
A record temperature for the year of 26.2 degrees was recorded at Shannon Airport on Sunday.
There will be a split between temperatures in the north and west and the south and east of the country for the rest of the week, with Connacht and Ulster seeing temperatures of between 18 and 20 degrees, whereas highs in the south and east could reach 25 degrees.
Monday is likely to be the warmest day this week in Ireland with temperatures moderating for the remainder of the week before rising again next week as a heat plume crosses northern Europe.
Ireland will be on the outer fringes of the hot air from north Africa which may bring near record temperatures to parts of northern Europe.
The Met Office in the UK has declared a heatwave in the south of Britain for the rest of the week (a heatwave is five successive days when the temperature is five degrees above normal). Temperatures there are expected to reach 33 degrees in London on Monday, the highest temperature there so far this year.
Forecasts at the moment show temperatures of 45 degrees in Spain, 43 degrees in France, 40 degrees in Belgium and the Netherlands with the possibility of 37 degrees in the south-east of England. An earlier model indicated a temperature of 43 degrees in England which would be an all-time record.
Met Éireann forecaster Emer Flood said Ireland will escape the worst of the exceptionally hot weather, but it will still be very warm next weekend.
“There is going to be a hot plume of air moving over France and south-east England which could see some extreme temperatures next week,” she explained.
“Ireland will be on the edge of that, but temperatures will be rising into the high 20s in the south-east on Sunday.
“Sunday is looking dry and bright across the country. There is a potential for mid-20s in a lot of areas, the warmest weather is expected again in the south and east of the country.
“There is a chance of very warm temperatures in the early days of next week. It will be in the mid to late-20s, but you are unlikely to see 30 degrees.”