The heatwave in Galway will be short-lived with Met Éireann forecasting unusually high temperatures for just two days before conditions return to normal on Tuesday.
And while there will be plenty of sunshine in Galway tomorrow, the forecast for Monday afternoon is mostly cloudy.
Coastal areas will also be much less affected by the heat, with temperatures in parts of Connemara not expected to exceed 23 degrees.
Galway city will see temperatures in the late 20s on Sunday and Monday and it could be over 30 degrees in some areas of east Galway.
A status yellow warning for Sunday, Monday and Tuesday was issued for all counties in the Republic with daytime temperatures of 25 to 30 degrees, and possibly up to 32 degrees in places on Monday.
Nighttime temperatures will range from 15 to 20 degrees.
The hot weather can cause heat stress, especially for the more vulnerable of the population, and Met Éireann also warned of high solar UV index and an increased risk of water-related incidents.