Weather warnings are in place across the country and officials are preparing for an extreme cold snap.
Here is a glance at some of the numbers:
- 104 - The number of extra beds secured by the Dublin Region Homeless Executive for rough sleepers. Up to 60 additional bedspaces are also available in a city centre sports hall.
- Six - The expected snowfall in centimetres by Wednesday morning.
- Minus five degrees - The overnight low forecast into Tuesday
- 130 - The number of gritters available to salt main roads in Northern Ireland, as well as 12 specialist snow blowers if needed.
- 100 - The number of litres of water lactating dairy cows drink each day, according to the Department of Agriculture, Environment and Rural Affairs. Farmers have been advised to have at least a 24-hour stock of water in reserve in case of burst pipes.