'Weather will not be a factor on the outcome'
Voters will have to avoid scattered showers on their way to the polling stations.
Met Éireann has predicted that the weather shouldn't be an obstacle tomorrow.
"Although there will be rainy spells, there will also be long, dry interludes, so we can expect a lot of dry weather throughout the day," a forecaster said.
Dr Adrian Kavanagh, of the Department of Geography at Maynooth University, says that on previous occasions, such as the Divorce Referendum in 1995, wet conditions have had a serious impact on voting patterns.
"The margin of victory was just 9,114 votes, meaning that the referendum would have been lost if just over 4,500 of the Yes voters had changed their minds, or if 0.92pc of the 994,892 non-voters had decided to turn out and vote No," he explained. "The weather on the day was believed to have had a bearing on the result, with bad weather in the west, where the No vote was strongest, and better weather in the east, where Yes support was highest."
Dr Kavanagh said: "You would expect that scattered showers shouldn't be enough to influence people too much."