And there is another thing to keep in mind. The odds of rain change by day. Today was 50%. But the odds of it raining on day 2 will change overnight. And the odds of it raining on day 3 are even less certain.
As a gardener, if there were 50, 40, and 30% chances of rain in successive days and my garden meter said the soil at root level was "dry", I would water deeply day 1.