I think you are describing it pretty well, and I've noticed the same thing. The farther into the future the forecast goes, the higher the probability is that it will look like the historical average.
One thing that I've found to help a lot is to go to weather.gov and look at the "forecast discussion". Often it will help to understand what types of uncertainties exist within the forecast.
It isn't unusual to see notes that make it really clear that 24-48 hour variations are expected, or that massive differences will exist based upon hard to predict variables. "Hey we think it will rain heavily as far south as X, but actually it might end up staying north of Y in which case X will stay dry"
It is easy to see how hard it can be even if the forecast itself turns out to be fairly accurate at a high level.
One thing that I've found to help a lot is to go to weather.gov and look at the "forecast discussion". Often it will help to understand what types of uncertainties exist within the forecast.
It isn't unusual to see notes that make it really clear that 24-48 hour variations are expected, or that massive differences will exist based upon hard to predict variables. "Hey we think it will rain heavily as far south as X, but actually it might end up staying north of Y in which case X will stay dry"
It is easy to see how hard it can be even if the forecast itself turns out to be fairly accurate at a high level.