There are many different site specific considerations to take into account.
Latitude
Your specific latitude determines that angle that the sun will hit your dwelling.
Immediate surrounding factors
Be familiar with the different elements that interact with the property. There could be standing objects such as trees or buildings that may block the winter sun.
The chosen site may also have prevailing winds or be in a mud slide zone. (I know of a person that bought a beautiful mountain home and happily lived in it for a few years. One spring it rained more than usual, and he found out that the house was in a mud slide zone.)
Regional factors
Climate and the proportion of sunny days to cloudy days. A house in Seattle, Washington will experience more cloudy days than a house in say, Montrose, Colorado. A house in Colorado in the plains will likely be different and take into different considerations than a house built in the mountains, and a greater snow load will also need to be taken into account. It’s all different, and thus, where we find the beauty in the challenge.
There is beauty in troubleshooting and taking into account regional and surrounding differences according to each site. This is why we have this site, and want to highlight the ingenuity of architects, builders, and those that live and work within passive solar buildings.