Keep Warm, Keep Well
Cold wesather alerts are issued by the Met Office. You can find the latest cold weather alerts at: https://www.metoffice.gov.uk/public/weather/cold-weather-alert/?tab=coldWeatherAlert&season=normal#?tab=coldWeatherAlert
If snow or severe freezing is expected, you might also want to see whether a severe weather warning has been issued at https://www.metoffice.gov.uk/weather/warnings-and-advice/uk-warnings#?
In the case of cold weather it is important you keep yourself safe and well. You can find out more in the Government's "Keep Warm, Keep Well" leaflet.