Some trick-or-treaters could be in for a damp evening, with a Status Yellow thunderstorm warning in place for counties Carlow, Kilkenny, Wexford, Wicklow, Cork and Waterford from 7pm until 10pm.
Rain in the affected counties will be heavy and thundery at times. Impacts will include spot flooding and difficult travelling conditions.
It comes as Hurricane Melissa ravaged Jamaica, Cuba and Haiti this week as the death toll across the three countries nears 50.
Melissa will arrive in Ireland by Sunday or Monday, by which time it will no longer be a hurricane and will have lost its ferocity.
However, it could still trigger storm surges and gusts of up to 83kmh, forecasters have said.
Met Éireann has forecast some heavy rain, but other climate experts believe it will be a storm.
Dr Samantha Hallam, an ocean and climate scientist at Maynooth University, said it is “difficult to tell regarding the storm strength for Ireland currently”.
She added that the country could experience gusts of up to 83kmh by Monday morning.
Met Éireann has also issued a Status Yellow gale warning from Valentia to Malin Head, valid until 10pm tonight.
Another gale warning is in place from Fair Head to Mizen Head on the Irish Sea until 6am tomorrow.
Stock photo: AP Photo/Michael Probst
7-Day Weather Forecast: October 27th to November 2nd
Wet conditions today cleared by this afternoon for most areas. However, showers will build up again from the south over the late afternoon, early evening.
Heavier thundery falls are expected with daytime temperatures of 11C to 14C. Tonight will see rain over the north with temperatures between 5C and 8C.
Tomorrow will start off particularly rainy in the west before showers spread further inland with temperatures of 9C to 12C.
Saturday night will be chilly at between 3C to 7C, though is expected to remain largely dry.
Sunday will start off mostly dry and bright with showers confined to the Atlantic coast. Cloud will move northeastwards to most areas by late afternoon along with outbreaks of rain and highest temperatures of 9C to 12C.
Met Éireann said Monday will be wet and windy with widespread rain, becoming heavy at times. Highest temperatures of 13 to 15 degrees.
The forecaster added that low pressure will dominate with “unsettled and mixed” conditions for next week.