I like showing houses to buyers on rainy days as it is the ideal time to gauge how each house handles rain. How does it smell? Is the humidity high in the basement? Is a dehumidifier running and connected to a drainage mechanism such as a sump pump or condensation pump?
On the exterior, are all the downspouts connected properly so that water is flowing away from the house? Are gutters adequately handling the rainflow? Are they clogged and causing water to drop close to the house and cause a potential moisture/mold issue inside? Is water collecting in any area around your property?
Rainy weekends are a good time for all of us to do a quick inspection of our houses as if we were potential buyers. Let me know if you need any resources for addressing water issues so it can stay dry and healthy.