Cold and wet weather can cause leaks and seepage in buildings due to thermal contraction. Most materials expand when they are heated, and contract when they are cooled. Concrete will expand or contract due to fluctuations in temperature, so concrete structures will shrink during the cooler months and as a result cracks and joints will widen during this time.
The cooler season is normally a fairly dry season, so expanding cracks and joints may not cause any issues regarding water ingress. Now that the wet season is extending well into the cooler months, cracks in your concrete slab, cold joints or wall to floor joints that have never leaked in the past, may start to show signs of water ingress when it rains during the cooler months.
Additionally, the soil is already high in moisture from recent big rain events and periods of continuous rainy days. Cold temperature, wet weather, hydrostatic pressure and the lateral pressure from saturated soil can push the excess water into basement slabs, foundations and retaining walls where water can seep through cracks, porous building materials, holes, joints and/or compromised waterproofing.
