A Met Éireann snow and ice warning is in place for counties Donegal, Leitrim, Sligo, Cavan, Monaghan, Clare, Cork, Kerry, Limerick, Galway, Mayo, Roscommon, Longford, Louth, Meath, Offaly and Westmeath until 9am today.
The national forecaster said there will be snow showers in these counties leading to some accumulations, and it will be icy too.
Schools in an area under a Status Yellow warning have the discretion to decide whether to open, taking account of a number of factors, including whether school buses are running.
Yesterday, it was confirmed that around 30 schools in Donegal and several in west Cork closed.
According to Bus Éireann, which operates the school transport scheme, some school buses were also cancelled in counties Clare, Kerry, Leitrim, Mayo and Sligo.
A spokesperson for Bus Éireann said school transport does not operate during red weather warnings, “but otherwise as the routes are so varied the best determination is made at local level”.
In any county, the conditions may vary, which could mean that the risk to school bus services and school opening may not extend throughout the county.
A spokesperson for the Department of Education said any decision by a school to close is taken in the interest of child safety, having assessed the local risks and having consulted, as appropriate, with school transport operators.
The spokesperson said there was no onus on schools to report closures to the department.
Apart from school buses, other factors that schools may consider include the ability of parents, students and staff to safely negotiate local roads, conditions in the school and its capacity to ensure the health and safety of students.
Under current department rules, there is no requirement for schools that are closed due to adverse weather to switch to remote teaching.
Where tuition time is lost, boards of management are asked to consult with principals and teachers to see how the curriculum for each class/year group can be completed before the end of the year.
Schools have flexibility about how that is achieved, and where the loss is significant, the department suggests a range of approaches including prioritising tuition over other non-tuition activities and reducing, where possible, the length of mock/house exams.
Meanwhile, today will be another bitterly cold day with a mix of sunny spells and scattered wintry showers, most frequent across the north and north-west.
Highest temperatures will reach between just 2C and 5C.
It will be another cold night with scattered wintry showers, mainly affecting Atlantic coastal counties, and becoming persistent in parts of the south-west.
Lowest temperatures will range between -3C and 0C with frost and icy conditions developing. Tomorrow, temperatures of between 3C and 7C are forecast, falling to -2C overnight.
Met Éireann said temperatures are expected to increase by the weekend.