The trouble is, any skill above climatology beyond about 5-7 days is very very low.
So sites could offer such forecasts, but they wouldn't be worth much of anything.
The main thing they could offer that has any use that is an indication of what typically happened in previous years (i.e. climatology)... but unfortunately I don't know any site that offers such on an hourly basis. We could use more of that! Still, if you're familiar with the area you're looking up for, you're probably fairly used to the typical weather for a given time of year.
There has been some small skill at making blurrier longer range forecasts... basically estimating either within a large range (such as hurricane forecasts) or (more often) giving probabilities of whether the weather will be above or below that climatological expectations.
(Basic summary for those wondering about how successful some such probabilities are: on these graphs, 0 is no skill, 100 is perfect skill... so 8-14 days temperature and precip have a bit of skill, but lower for temperature and almost no skill for precipitation for a monthly forecast given 2 weeks ahead of time)
But such long-range forecasts don't have nearly the precision to offer hourly forecasts to be of any legitimate use.
So basically if you're eagerly planning for a trip in 10 days or a wedding in a month or two, you're much better off staying far away from such novelty longrange forecasts until the event gets much closer. Until then, all you can really figure on is what's typical for the given time of year.