This question cannot have an answer, because the Cammino Materano is in southern Italy and not in one of those tropical areas where there is a rainy season in which these observations are practically seasonal. I have encountered light rain at low intensity. In the 6 days when I walked the Via Lucana between the end of December and the beginning of January I never saw rain. Sometimes, so much so that they talked about it humorously also on some national news outlets and there is this video published by La Repubblica that immortalized the situation of that day. It has happened occasionally under a bit of timid light rain. In the 6 days when I walked the Via Lucana between the end of December and the beginning of January, I never saw rain.