You can still recover compensation if you fall in a business on a rainy day. The fact that it was raining will only really affect what the law expects of the landowner. A landowner is required to take reasonable steps to address dangerous conditions on the property that they know of. What is reasonable might change slightly when a rainstorm is ongoing. For example, you might walk into Target, and the floor might be soaking wet. But employees may have just mopped five minutes earlier, with the floor being wet again by incoming customers. The law won’t usually expect the store to mop continuously; they only need to do what is reasonable. Your attorney can assess the facts of your case and give a more clear answer on the strength of your claim.