Status Yellow warnings are in place for six counties as heavy rain and strong winds affect parts of the country.
Met Éireann has warned of localised flooding and difficult travelling conditions for Galway and Mayo, where a Status Yellow rain warning is in effect until 8pm.
A similar rain warning for Cork and Kerry is valid until 8pm.
Meanwhile, a Status Yellow wind warning is in place for Cork, Kerry, Waterford and Wexford until 11pm.
Met Éireann has warned people to watch out for fallen trees and for waves overtopping near the coast.
The UK Met Office has issued yellow wind warnings for Antrim, Armagh, Down, Fermanagh, Tyrone and Derry.
It is valid until 11pm, with strong winds and heavy rain likely to bring disruption to these counties.
Met Éireann meteorologist Linda Hughes said the weather across Ireland today has been “pretty unpleasant”.
She said there will be further “heavy rain” through this evening and “strong winds” along the south coast.
Speaking on RTÉ’s Drivetime, Ms Hughes said more rain will move in tomorrow.
However, she said the timing of the showers will “suit most trick or treaters”.
“It’s going to move up over the country during the morning and early afternoon and then that will clear away,” she said.
“So it’s looking pretty good for Ulster, Leinster, and Connacht, for the early evening time.”
“It’ll be generally dry with just isolated showers – but I would suggest the earlier the better if you’re going out trick or treating,” Ms Hughes added.
She gave a less favourable forecast for Munster: “It is going to be wet in Munster, there will be some heavy rain through the late afternoon and early evening.
“So just, you know, bring some umbrellas,” she said.