Trick or treaters are being warned to wrap up warm as a cold snap is likely to bring a chill on Halloween night.
Last night parts of Ulster experienced an unseasonably early dusting of snow on higher ground.
Over the next few evenings, temperatures look set to fall below normal for this time of year.
According to Met Eireann, Wednesday (Halloween night), will see some showers in the afternoon with temperatures ranging between seven and 10 degrees.
However as the evening draws in, showers will clear and temperatures will fall. The national forecaster says there will be lowest temperatures of minus one to two degrees with some frost and icy patches possible.
"It is looking like a chilly few days," said forecaster Matthew Martin.
"Temperatures [are] three or four degrees below the norm at the moment.
"For tonight and Monday night we'd expect quite a widespread frost across the north and east, and again on Tuesday night. And a slight frost is possible on Wednesday night.
"So it is going to be quite chilly and obviously, take care on the roads."
The AA is also urging parents to give a torch or a glow light to any children going trick or treating on Wednesday, to ensure maximum visibility this Halloween.
Costumes that are flame-resistant, bright and reflective should be worn to ensure they can be seen.
Barry Aldworth from the AA says precautions need to be taken on what can be a dangerous night.
"Anything you can do which will make the child more visible and give an advanced warning to a passing motorist that there are children up ahead is going to help," said Mr Aldworth.
"Particularly in a case where the costume may be quite dark, no harm that they have a flashlight with them just so that they are that bit more obvious to a passing motorist."