Most spots had no rainfall on Delmarva today but some areas had around 2 inches! Our rain chance today was 40% which means that any one spot had a 4 in 10 chance of measurable rainfall. It looks like we were not far off. We calculate the rain odd by taking the chance of rain anywhere on Delmarva and multiplying by the coverage area we expect. I thought there was about a 90% chance of soem rain in the area and that about 40% of the area would see rainfall. 90x 40 gives a 36% chance of rain. I rounded it up to 40%.