As the name suggests, the Time of Silence refers as much to the land as it does to the people of the y Ddraig world.
In fictional 6th century Cymry this is the coldest, deadliest time. All the livestock are snugged up inside the shelters and nobody works outdoors or travels or even emerges if they don’t have to. Sometimes they are fully snowed-in and so they literally cannot get out their doors without brands and a team effort. Everyone hunkers down to get through the worst month and, outside, even the remaining birds are quiet, tucked in their nests busy surviving the cold.
Midway through Silence, (and at the mid-point between the Winter and Spring equinoxes) on the full moon is a fire/fertility festival, which was mostly observed within the home (given the impractical season) with candles or (at least) the hearth. It ensured protection and fertility for the crops and animals in the season to come.