Met Éireann has issued a status orange rainfall warning for bank holiday Monday - with midland, west and northwest areas set to be worst affected.
The warning is valid from 12pm tomorrow afternoon until midnight, with a forecast of intense thunderstorms.
Slippy roads, poor visibility, and local flooding will lead to "treacherous driving conditions", forecasters say.
Heavy showers are also expected in the north-midlands and northwest later today.
However it will stay generally warm today, with cloudier conditions in some areas.
Met Éireann says there will be a mix of cloud and clear spells tonight.
Meanwhile, gardaí are out in force this bank holiday weekend with dozens of check points in operation across the country.
Moyagh Murdock, CEO of the Road Safety Authority, is urging drivers to abide by the law.
She says there has been a big increase in weekend road deaths so far this year:
