Here is the tune. Tempo is Andante.

X:1
T: Idle Days in Summertime
T:Bugeilio'r Gwenith Gwyn
M:3/4
L:1/8
B:William Cole, Folk Songs of England, Ireland, Scotland & Wales (Charles Hansen, 1961, pp. 228-9)
K:D
D3/2 F/ A3 F|G3/2 G/ F3 G|A F D3 F|A A3zF|
G3/2 A/ B3 G|F3/2 G/ A3 F|F3/2 E/ E3 C|D D3z2|
D3/2 D/ d3 B|G3/2 G/ G3 F|E3/2 E/ e3 d|(cB)A2zF|
G (G/A/) B3 G|F3/2 G/ A3 F|F3/2 E/ E3 C|D HD3Z2|]