Freeze bites hard in Wales with temperature of -14C
Temperatures dropped to as low as -14C (7F) in mid Wales overnight as the country woke up to a severe frost.
Snow showers are falling in the north-west of the country with Anglesey expected to be worst hit.
Drivers are urged to take care because icy roads are once again making roads treacherous.
Cardiff Airport is getting back to normal after departures were cancelled on Monday evening because of freezing fog.
Flights have resumed on Tuesday morning but some services have been disrupted because of the knock-on effect.
Passengers are advised to contact their flight operator.
The coldest temperature overnight is reported to be -14C (7F) at Tirabad near Llanwrtyd Wells in Powys.
Hawarden in Flintshire, saw temperatures of -8C (18F), while St Athan in the Vale of Glamorgan -6C (21F).
Wintry showers are expected to fall in north-west Wales for much of the day as temperatures remain very low.
Anglesey is expected to be hit by the worst of the hail, sleet and snow.
The cold is expected to last into Wednesday, before north-westerly winds on Thursday and Friday cause the snow to melt and bring temperatures back up to 7C (45F) or 8C (46F).
Drivers are once again being warned about icy roads as temperatures struggle to get above freezing.
The A55 on Anglesey was closed between junction six (Llangefni) and junction seven (Gaerwen) on Tuesday morning after a collision.
In south-east Wales, there were also warnings of fog on both Severn crossings.
First Cymru buses said icy roads were affecting some services in the Bridgend and Maesteg area.
Cardiff and Vale University Health Board said during Friday, Saturday and Sunday, 1,086 people attended the accident and emergency unit at University Hospital of Wales in Cardiff.
Another 272 people had attended the unit by late Monday afternoon.
Many of the injuries were linked to the cold with ice causing trips and falls.
Graham Shortland, interim medical director for the health board, said: "We would ask people to think carefully about whether they need to come to A&E.
"If they do attend, they should only be accompanied by friends or family as necessary."