From the BBC -
And in Wales, the Royal Mail says snow and ice could hit mail deliveries and collections in parts of four postcode areas - LL, LD, SY and SA.
The postcodes cover north Wales from Anglesey to Wrexham, parts of Powys and Ceredigion and south west Wales including Swansea, Neath Port Talbot, Carmarthenshire and Pembrokeshire.
Hopefully these delays won't last too long. More here.