A fool I was to sleep at noon,
 And wake when night is chilly
Beneath the comfortless cold moon;
A fool to pluck my rose too soon,
 A fool to snap my lily.
My garden-plot I have not kept;
The moon has multiple associations. Most commonly it is thought romantic and mysterious, but is also associated with madness and sinister forces. In  Gothic  terms the moon is associated with werewolves and magic. 
 Here Rossetti subverts our expectations. The moon is ‘comfortless’ and ‘cold’. The hard, percussive ‘c’s emphasise its hostility to humans.
A Daughter of Eve