It was a mainly fine day today, but tomorrow is going be a cloudier affair with a spell of rain. At least it will be a little milder.
Overnight a warm front drifts south with just light and patchy rain on it, meanwhile a cold front eventually shows it's hand in the north. The cloud will mean it won't be so cold a night with lows of more, so we should escape a ground frost.
Sunday is likely to be the reverse of Saturday. Rain in the north early on in the day drifts south. This could produce some spells of heavier rain for a time before weakening. Into the afternoon, south Wales receives the rain (what's left of it), further north there should be a good clearance of cloud the north coast should see sunshine to end the day. Everywhere will be milder with highs of 9C.
As the name suggests a cold front will introduce colder air, so while it will be sunnier again, the temperatures will take a tumble.