Soil is subject to moisture changes from inclement weather. Pool builders cannot operate in wet soil due to the increased risk of machinery getting stuck and the excavation site caving in.
The type of soil in your area dictates the way it responds to moisture. For example, clay soil holds moisture better than sandy soil, making it less likely to collapse on the excavation site during heavy rains. However, it also takes longer for the moisture to completely dry out, leading to longer delays.