Met Éireann has issued a status yellow thunder warning for 15 counties.
The warning is in place for all of Leinster, Cavan, Monaghan and Donegal.
They are warning of “scattered thunderstorms today and tonight, with lightning, hail and a risk of localised flooding”.
The warning, which came into effect at 11am, will remain in place until 8am tomorrow.
Earlier, authorities warned of thunderstorms in Northern Ireland over the next few days.
The UK Met Office is warning that on Monday, some places in Antrim, Armagh, Fermanagh, Tyrone, Derry and Down are likely to see “severe thunderstorms”.
The status yellow warning is in place until Wednesday, with the Met Office saying “there is uncertainty in location and timing”.
For the rest of Ireland, Monday is set to see showers “extend from the south through the mid-morning and afternoon, with heavy and thundery bursts possible especially in Leinster and Ulster”.
According to Met Éireann, "occasional bright spells are possible” in the west with cloud increasing through the afternoon.
The showers should make way for a “dry, mild and humid night”.
Met Éireann is predicting that on Tuesday, it will stay generally dry with a few sunny spells and “the possibility of some isolated showers”.
They say the cloud will break and the country will see “some good sunshine” during the evening.
Temperatures are set to hit the mid-20s, with highs of 24 degrees predicted.
The rest of the week will remain warm, but the weather will be unsettled.
Wednesday will see a dry and cloudy start but it will brighten up.
However, Met Éireann says that isolated showers are possible.
They say there is a “good deal of uncertainty” around Thursday’s weather.
They added that “current indications” suggest a mainly dry start to the day, before showers “move in from the south" and become "widespread with the risk of thundery downpours”.