A combination of showers and sub-zero temperatures overnight are expected to bring ice to Brighton and Hove, the Met Office warns today.
A severe weather warning is in place from midnight to midday tomorrow, with ice expected on roads, pavements and cycle paths, bringing the danger of slips and falls.
Railways could also be affected.
The council’s gritters will be out tonight, and the severe weather homeless shelter will also be open.
The Met Office said: “A band of rain will clear Northern Ireland on Monday evening with surface temperatures falling away behind this and icy stretches likely to form on some untreated surfaces.
“Wintry showers will push into the country from the northwest overnight, with a few centimetres possible across northern and western counties, especially over higher ground.”