Unless you have the actual weather station that data is pulled from, exactly at your location it could be totally accurate for the location of the actual weather station. So, it's otherwise based on forecasted data. A 50% chance of rain means that there is a 50% chance of rain at some point in "forecast area". In the US, forecast areas can cover 20 to 50 counties in whole or part. In my case, in a large metro area, the weather station used is actually 8 miles from my home. So, what you are seeing is probably totally accurate in some place in the forecast area. 50/50 chance of being right or wrong.