Maternal and newborn health disparities and impacts of climate change present grand challenges for global health equity, and there remain knowledge gaps on how these challenges intersect. This study examines how mothers are affected by seasonal and meteorological factors in Kanungu District (Uganda) through a community-based study with mothers and health workers. The causal pathways through which weather and seasonality may affect size at birth as reported by Kanungu mothers were consistent with those frequently reported in literature elsewhere, including maternal energy balance (nutritional intake and physical exertion output) and seasonal illness. Non-Indigenous mothers frequently relied on livestock assets or opportunities for less taxing physical work than Indigenous women, who had fewer options when facing food shortages or transport costs. Findings point to specific entry points for intervention including increased nutritional support in dry season periods of food scarcity, increased diversification of wage labour opportunities,