A yellow weather warning for snow and ice came into force on Monday afternoon.
The Met Office has warned of the potential for difficult travel conditions as the alert started at 3pm and continues until 10am on Tuesday morning.
Some roads and railways are likely to be affected with longer journey times by road, bus and train services.
There is the potential for icy patches on some untreated roads, pavements and cycle paths – and the risk of slips and falls.
According to the forecaster outbreaks of rain will arrive from the west during Monday afternoon, turning to sleet and perhaps wet snow at times during the afternoon, evening and first part of the night.
Snow is expected on high ground above 200 to 300 metres, where several cm snowfall is likely, and perhaps 5 to 10 cm across the higher parts of the Sperrins and Mournes.
Settling snow looks unlikely on low ground. However, as skies clear overnight, temperatures will fall widely below freezing with ice forming on untreated surfaces. This will lead to difficult travelling conditions.
The Met Office warns that you should give yourself extra time for journeys and try and stick to main roads which are likely to be less slippery.
If driving, make sure you have some essentials in your car in the event of any delays (e.g., warm clothing, food, water, a blanket, a torch, ice scraper/de icer, a warning triangle, high visibility vest and an in-car phone charger).